when in hot water only mode, hot water is entering the rad circuit. presumably the diverter valve is not sealing off the rad outlet. service manual gives no exploded view of the valve assy.

dave h t, October 2009

Mine was given the same problem while in HW mode only,the boiler wasn't firing up, I noticed the pin wasn't moving out to make contact with the micro switch, even when I manually switched the micro on the hot water was diverting to the Rads, changing the Diaphragm on the HW demand valve sorted this issue, thank god it wasn't the whole Diverter.

TerryD, March 2015

It is possible to remove and clean the diverter valve assembly. Possibly no replacement is required.
I had one that started to cause a problem with the radiators getting hot when the bath tap was running. This did occur after about 5-6 years in service. It turned out to be full of deposits that could be cleaned off.

TO DO THIS TASK A COMPITENT PERSON WOULD HAVE TO SHUT OFF THE GAS AN ISOLATE THE ELECTRICAL SUPPLY TO THE BOILER. THE UNIT SHOULD BE COOL BEFORE OPENING TO AVOID THE RISK OF SCALDING. Then the under the unit the shut off valves for the water inlet and the heating in and out can be closed.

If the unit is cool, remove the front panel and the 2 screws to allow the control panel to flop down. The diverter valve is bottom left on the base of the casing retained by 2 screws.

The boiler can be drained using the drain valve on the right hand side. Be careful because there is some quantity so be ready to catch it!

Removing the valve involves taking off the micro switch on the front. Detach the two small pressure differential pipes with a 10mm spanner, releasing the two screws behind the retainer for the front diaphragm housing and withdrawing the housing.

The two cap screws on the right hand side can be removed where it is connected to the part that attached to the heat exchanger. The connection to the heating out pipe can be released from underneath the boiler.

Remove the top micro switch further back for access then carefully disconnect the pipe in the back which is attached as push fit with a retaining clip.

Remembering the two retaining screws it should be possible to remove the diverter valve.

The body of the valve itself comes apart by retaining the body and unscrewing the back of the housing.

Probably the valve just needs a good clean so the shaft(s) slide nicely again.

Anon, January 2011

hi dave, did you sort the problem, i'v got the same issue on my 105e boiler, hot water entering rad circuit and not heating water, would appreciate any advice
cheers dave d

dave, December 2009

Any idea where you van get a diverter valve for that price? I'm being quoted £90!! I live in Kent nr Rochester

Richard, November 2009

Where can you "buy and exchange" a diverter valve for a Baxi 105E ??
Thanks

Martin, November 2009

try the microswitch first.... that is only a few £'s from screwfix or maplin etc. other than that buy and exchange the whole valve £ 35.00 + depending on type

zephania, October 2009