In addition the my previous question (with same title), I managed to get the Central Heating (CH) working for an hour or two (we let the system cool right down and had switched off Programmer/Timer and after an hour or so the CH system then worked for two hours!). Yet again this morning the CH wont work and rads are cold. We seem to have plenty of hot water though - is this something to do with the Hot Water (HW) and CH coming on roughly at the same time in the early morning (i.e. the Boiler 'overheating'?). The Boiler is margianlly noisier than it has been in the past - or is it that we are noticing such more when looking for faults? Yesterday when this fault - really - manifested itself we had the HW on a lot as we had visitors and lots of HW was required for extra washing-up etc.. My thoughts are now; is to Boiler getting too hot and 'failing safe' prematurley?

This appears to be the worst possible fault as it is, in effect, intermitent!!!

Many thanks in anticiaption.

Completely confused - Swindon

Martyn R., November 2009

Cheers martyn for the update havn't been on this site for over a year but remembered your problems and thought i would see if any updates were posted.. glad everything is now sorted for the winter!

Brucey, September 2010

Hi all,

As promised a conclusion to the ongoing saga!

I have found that when replacing the 3 port-valve that the actuating arm (plastic arm which travels across and operates the micro-switches/end - switches etc.) was worn and broken, with small parts having broken off - thus the arm would no longer operate correctly - and neither would the CH. The final and complete Central Heating failure was due to a bigger part - relatively speaking - of the arm breaking off. The valve body and motor seem okay though (motor will be kept as a spare).

The pump was also replaced - as mentioned before we had a 'new old stock pump' (SMC Comet 2) which is, so I believe, NLA. The orginal had failed and when replacing with the new one, it was found that the original didnt have any form of sealing between the gate valves and the pump inlet/oultets (it had leaked once before, about 8 years ago, from these joints and I tightened such up - it was only making a seal with black crud - Fernox when vented to air? - and verdigris!!). The unions/gate valves were a challenge to get apart, yet they did in the end - all very confined in the airing cupboard! I also found out that the pump was installed upside down - motor at the bottom - so as to, I presume, ease/have access to the wiring panel/motor/rate controls etc., to mount the pump this way is, according to the fitting instructions, against the manufacturer's advice! I had little choice but to follow suit unless I was to remodel the whole installation!..... I also discoverd that the wiring had been modified on the wiring panel of the pump - odd yet safe - again I had to reinstall as per the original installation - I had little choice and as the manufacturer was no longer contactable I wasnt able to seek advice in a hurry....

The pipe ends - for the gate-valves/pump instalation - were cleaned up so as to accept new fittings and olives etc..

After fitting the above items, the system was topped up with clean water and with Cal-Chem (3 action type) which seems to have quietened the boiler. I did notice that this time, after a full drain-down, there was lots of air in the system (rads, HW coil in cylinder etc.) which took a long time to bleed off. I have done full drain downs and flushes before - yet this seemed to take longer. There is also the issue of topping up and running the pump for a few seconds - so as to get the water/additive moving around the sytem - and then when the pump makes a noise, shutting the system down and bleeding off the intial excess 'air' from the bleed off valve at the top of the system - I had to repeat this 6 or so times. Then when the system is full, it is time to bleed the rads - with ours I started at the furthest (downstairs) and worked my way back, room, by room to the upstairs. With the rads bled, it was time to switch in the HW again, and bleed the air from that from the bleed off valve at the top of the system.

All seems well at the moment, a little air has materialised again, and will need another quick bleed off. All the joints seem to be dry and the 3 port-valve and the pump are working okay (although the pump seems a little noisier than before - although it's a long while since such has worked well anyway(!) - and the manufacture states that such is normal for a few days after installation.

As with the timer/programmer last year I used City Plumbing (no connnections with the company other than as a happy customer) and their own 'Iflo' products (in this case the 3 port-valve), which appears to be the same as ICL/Drayton product yet cheaper. The new 3 port-valve has a push on/removable acutator assembly - which wasnt made all that clear in the instructions, yet is a great fetaure - especially in the confines of an airing cupboard! - may be this is now a service/replace/repair item, i.e. if it fails or wears out then it can be easily replaced (I dont know if it is available as a 'spare' though).

I hope this comprehensive explanation - saga! - may help others, in these cash strapped times, with similar CH/HW problems - thanks to all of those who have contributed.

I have heard from two plumbers, recently, who have seen similar CH/HW problems in customers' homes, and have been baffled by the 'symtoms', which have taken a couple of days to figure such out - so no wonder it took me a while! These 3 port-valves seem to almost be forgotten at times - as they lurk inside airing cupboards etc. - yet like everything else they cant last forever (I did read that they can last upto 30 yrs, ours was 20-21 yrs old and the motor and valve were okay yet the plastic arm had given up the ghost!).

BTW - in closing;

The general advice for fitting a new pump is to flush the system first. We had no choice as the pump had failed, yet the water from the rads etc. was clear when drained off and nice and clean, the header-tank had a redish verdigris within it - something we seem to suffer from here and something which our local water company seems aware of yet wont comment on! So I emptied out the header-tank and gave it a brief clean, the Cal-Chem will break down any muck in the system and although a 'non drain-down additive', I plan to drain-down in the Spring and add another bottle upon refilling (£8-9 per bottle). The Cal-Chem breaks all the crud down so that it flows through the CH system without problem (the manufacturer uses the analogy of a sugar cube in a cuppa) - I hope it does what it says on the tin!

All the very best.

Regards,

Martyn R., September 2010

I promised that I would get back here with my findings - better late than never! :-)

I hope that this Thread helps others, in these cash strapped times!

Anyway on with the 'story' - all the wiring issues were checked in accordance with 'Brucey's' comments and all seemed okay.

After many challenges - life the universe and everything else over the past 8 months or so - the Central Heating was working okay up - with the occasional 'blip' -until the Spring when we used it less and less - and all seemed well.

Just recently my 'better half' asked for the Central Heating (CH) to be put on - for a short burst every now and again - and the fault materialised yet again. Now seems to be working again after a couple of failed attempts over the perion of a couple of days - this August (the time of writing) seemed a little more cold and damp than usual, we usually put the CH on in October (roughly the time of my first Post/the last failures etc.).

This all leads me to think that the 'End Switches' - in accordance with Brucey's comments - have an intermittent fault or are dirty after lack of use through the Summer months etc. (I know that this latter comment may not apply for/to microswitches) ........

I was given - in the summer - a 'new old stock' pump which was in brand new unused condition (we had already ascertained that the pump here wasnt faulty, just old'ish - 19-21 years old) and I am of the mind to change the pump, and the 3 Port Motorised Valve as an 'overhaul' to the system and so as to put an end to the intermittent nature of this fault. I will also, at that time, drain down and top up the system with an additive (maybe 'Cal-Chem') as the boiler seems - yet - a little nosier again this year..

My main thoughts/questions are;

Looks like it would be cost effective to change the Pump Valves (top and bottom of Pump) as they seem tight (even with a squirt of WD 40 and I cant be sure that they are working effectively, if I am to change the pump. Are the 'Gated' or 'Ball' types the best to use (I have been fitting Ball Valves to taps/tails etc. whenever the need has arisen as they make life much easier in the longer run), one Plumber I spoke to said that he doesnt like using Ball Valves for/as Pump Valves as they fail whereas 'Gated' valves dont (my - limited - experience appears to be otherwise!);

Does a replacement Synchronous Motor come with/ contain the 'End Switches'? Or even if such does would it be better for me to change the whole lot - the complete 3 Port Valve - for another twenty years of trouble free service (rather than change the Synchronous Motor and then something else fails with the the 3 Port Valve! - I can purchase a 3PV for approx. £45.00)?;

Has anyone any experience of 'Cal-Chem', which is a 3 in 1 system protector, noise reducer, scale inhibitor (we also have a scalewatcher for the Mains). I have used Fernox in the past which still seems to do it's job over many years - yet is not a noise reducer etc. Cal-Chem, seems easy to use, never needs draining - just topping up - and seems cost effective too etc..

Thanks in anticipation for any replies, comments and help etc.

I hope that this little Thread will help others with similar issues.

By the way, I havent looked anywhere else on this site for answers as I thought it best to come back here so as to finish what I started ;-) LoL!!

Thanks again,

Martyn R.

Martyn R., August 2010

Brucey, Hi!

Thanks, I was thinking about what you wrote before and along the same lines as trying to work out how to test the unit - however you have a greater technical ability and knowledge than me so you have answered such before I could ask - accurately too. Your advice will be invaluable.

All is well with the system at the moment CH/HW are working. When time permits I will - as a matter of course - perform the tests that you have suggested.

My mum was rushed to hospital and is critically ill in Intensive Care so things are very challenging here at the moment - what a three weeks we have had! So CH and HW etc. will have to left as is for the mo.

Thank you for your superb support it is very much appreciated. I will update here when I can find the time to perform the tests - which you have suggested - that will hopefully avoid any future spontanious/random failures e.g. the system fails at the worst possible time!

Thanks once again,

Best regards

Martyn R., November 2009

The more you describe the fault the more i am convinced on the divertor valve, if you have a multimeter , when you next have no heating turn off the water and check the central heating junction box

For heating to work you must first have voltage from the room stat so you will be looking for 240volts on the white wire in the junction box, this means the room stat is calling for heat.

This will send power to the motor and through a couple of end switches send 240volts orange wire to the pump and boiler, if power is absent at orange i would suspect the end switches are failing.

Also just a thought.... with power off check the wire that comes from the cylinder stat and is connected to the grey wire in the junction box, check for good connection in the junction box and on the cylinder stat.

Cheers

Brucey, November 2009

Peccavi & Brucey,

Thanks for the continued support - much appreciated.

Header Tank checked - levels etc. all okay, probably be drained next year and flush/add Furnox etc. But all is well with the levels, thought it would be, however with things such as car repairs taught to check the obvious first. But lack of water/liquid could cause overheat and cut out(?) i.e. through sticking/faulty Ball-Valve etc. All okay though on this front.

Brucey: Thanks, I thought that there was a stat/cut out/failsafe in Boiler - so no worries there which is a relief! Also system re-checked for air and that's okay too so eliminates another possible from the list (if ever it was to be an issue).

Peccavi: Thanks too, I have cleaned out any dust from Room Stat. Another item ticked off of the list too.

The CH is still working and so is the HW - so I'm not complaining at the moment - although still baffled by intermitant fault and a lack of a solution. The only thing I can think of is that the stats on Boiler etc. were 'fighting'/conflicting with Room Stat - I have reset Room Stat and Boiler Stat ever so slightly (not convinced that is the answer either but it is the only thing/setting which we've varied -slightly-with no reoccurance of the fault afterwards - been here 15 years and its never been an issue before though!). It could still be an intermitant fault with the Tri-Valve motor though. We've checked all other - external - wiring to and from component (system) parts -through and all looks and tests okay.

So thanks once again to both of you for your time and efforts in all of this.

I will update as and when anything else happens, hope this thread is adding to knowledge/help for others!

Martyn R., November 2009

cheers for the reply back, unlikely to be pump as there is a overheat thermostat on the profile and this would trip causing no heating/no hot water and would need manual reset. keep us posted!

Brucey, November 2009

http://www.diynot.com/forums/viewtopic.php?t=50043

P, November 2009

I am ashamed to admit that I don't fully understand the wiring associated with the diverter valve - it is possible under some circumstances that a fault in a microswitch can cause the boiler to fire up when it's not being asked to (yes I know you do not have this problem) my point is that the call for Central Heating signal might be routed to the boiler through the switches in the valve head - just a wild guess no more - you need to encourage the fault to materilaise - switch off the Hot Water demand so as not to be confused and go around tapping things electrical with a wooden spoon - have a buddy listen at the boiler for signs of action...

Here's a description which I have read (twice) but have yet to fully understand... My weakness I feel - not the writer's...

http://www.diyfaq.org.uk/plumbing/controls/midpositionvalve.htm

Continuing good luck...

Peccavi, November 2009

Hi, Brucey & Peccavi - thanks!

Brucey: I have checked the tri-valve and when observed/tested it does seem to work okay - that could still mean an intermitent fault as you have mentioned. I will keep a 'weather eye' on it though due to the intermitent nature of fault - good advice thanks!

Peccavi: Thanks, yes I have given the room stat a quick clean, as I have exprienced such before and it is surprising just how much dust gets in such devices! - Thanks for that too.

We are due to double check the level in the header tank and that the ballvalve is working okay i.e. so that there is enough water/fernox in the system and that the boiler isnt failing safe - I dont think this is the issue, however it's another thing to tick off of the diagnostic list and good to check periodically.

As I am writing this both the HW & CH are working - partner home with 'flu - so all is working again, which is good but baffling! We have also considered the possibility of a stalled pump due to trapped air - although the pump and system are meant to be self perging, the bleed screws for the pump are a bit of a so and so to get at if one has to bleed it manually.

Endeavoring to be methodical with all of this.

Will update this/here when resolved - thanks for prompt responces and the help, vmuch appreciated!

Martyn R, November 2009

It could well be the syncron motor in the three way valve, these are prone to intermittant faults with regard to no heating, check the arm on the valve moves over fully when heating is on, you can do this by moving it manually and are looking for no resistance to nominal finger pressure!

Brucey, November 2009

When your boiler gets a call for heat it will not know or care if the requirement is for hot water or central heating - it will burn gas and heat water until the signal asking for heat goes away - i.e. the storage tank stat is satisfied and / or the room stat is satisfied. If your boiler works fine for hot water then the boiler is good - Given a good boiler but no central heating I would firstly suspect the room stat.

When I pulled my hall ceiling down recently my room stat stopped working with all the dust in it - removed from wall - blown into hard - dusted with a brush & a squirt of WD40 soon had it working again. Ten mins and no cost...

Good luck...

Peccavi, November 2009