Hot Water Problems - Taps won't activate the boiler except in combination

VinBob

Hello - I have an odd problem and I was wondering if anybody could help:

My hot water is playing up. My kitchen tap works fine. My bath tap works fine. My bathroom sink tap is a Roca Mixer. It will activate the boiler no problem if the filter at the end of the tap is removed. If it is on the tap, it will not activate the boiler and there is no hot water. I have bought a new filter with which you can alter the pressure. Even turned fully open it makes no difference.

My shower won't activate the boiler at all.

However, if I turn on the bath and then the sink tap (with filter) it will activate the boiler. If I turn on the bath and the shower, they will both get hot water. Weirdly, if I turn on the sink tap and the shower it works.

I figure there is something wrong with the pressure in the system. I have no idea where the problem actually is though. I have considered that I have an airlock and connected the hot and cold water to flush it out with no effect. I do not believe it is the shower thermostat because when its on its fine.

I have a ten year old Baxi Condensing combi-boiler.

Has anybody got any idea what's going on? I'm at my wits end!

Many thanks.

Browntoa

Diverter valve in boiler has a pinhole ?

Valve senses demand for hot water and switches boiler to supply domestic hot water rather than heat rads

Alex1983

What model baxi is it? A lot have a diaphragm that operates the hot water. It could be worn or have a slight tear.

VinBob

Thanks for getting back to me Do you mind answering a couple more questions for me?

How much is a diagphram, how do I find out what type I need (if there are more than one) and how difficult would it be to repair it myself?

I obviously don't want to go anywhere near the gas, but if its just the boiler it should be okay, right?

Thanks again.

VinBob

Cheers for that

It's a BaxiCombi 105HE. What do you think?

Ta.

bertiewhite

You should be able to get a divertor valve refurb kit for a few quid - order by boiler model number. I got one from ebay a couple of years ago and it had a diaphragm, o-rings, washers, the lot for about £7.

Mine was a Baxi (same model I think) and I was able to sort it myself as no gas parts were affected.

VinBob

Same question for the divertor valve, if you don't mind

How do I identify the part, how much will it cost, and can I fix it myself?

Thanks

Browntoa

it looks like this


http://popularboilerspares.co.uk/boiler-spare-parts/baxi/baxi-combi-80e,-105e-diverter-valve-248061-detail?gclid=CjwKEAjw07nJBRDG_tvshefHhWQSJABRcE-Zh6SO3REE44MPv5uCypSGKTMcCOl2vaYEEkT6RqKDqhoCHavw_wcB


this is the parts


https://www.theheatxchange.co.uk/sku_BAX5111137.html?gclid=CjwKEAjw07nJBRDG_tvshefHhWQSJABRcE-Z8kWHLk4V5rX0ZmRzZdVOpfI7uo9Ry5anCH6j7ryg_RoCUrHw_wcB


video here


https://www.youtube.com/watch?v=qSYkaWmcxyw

VinBob

Wow - thanks! I'll take a look

Browntoa

disclaimer :- I'm not a boiler engineer but that's first guess for hot water supply problems on ALL boilers

VinBob

It's worth a go - much better than having to get a plumber out of God forbid buy a new one