Baxi Duo Tec 28 issue

[Peter Goble]

We had the boiler fitted in 2015, last winter it had an issue that when the hot water was turned on the pressure in the heating system started to rise and would go above 2 bar if it wasn't switched off straight away, the same issue happens is the heating is turned on. The problem righted it self after a couple of hours turning the tap on and off. The issue has now returned again, can anyone offer any advice as what this could be????

 

[CBW]

It sounds like an expansion issue, which is behind the combustion circuit cover, so will need a gas safe registered engineer to test, recharge or replace as necessary.

 

[Peter Goble]

Is it likely to be anything to do with the diverter valve and motor, will be changing these at the weekend?
What is an expansion issue???? and what is the budget cost?

 

[Peter Goble]

Having looked a bit closer at this issue, it only happens once the burner ignites with either hot water demand or central heating demand at that point the heating pressure gauge starts to rise and the boiler becomes "noisy"
The pressure in the heating is stable other than when this issue happens and once the demand is removed the pressure gauge returns to a normal stable working pressure.

 

[CBW]

Water expands when heated, and needs somewhere to go. There’s a vessel inside which has air in it, which has possibly diminished, perished or there’s a blockage. Nothing to do with the diverter valve or motor. The advice given - please heed.

 

[durhamplumber]

We had the boiler fitted in 2015, last winter it had an issue that when the hot water was turned on the pressure in the heating system started to rise and would go above 2 bar if it wasn't switched off straight away, the same issue happens is the heating is turned on. The problem righted it self after a couple of hours turning the tap on and off. The issue has now returned again, can anyone offer any advice as what this could be????

7 year warranty?

 

[Peter Goble]

Don't think the boiler came with a 7 year warranty although I did buy it from the Plumb Centre. Would the expansion vessel have a 7 year warranty????
How did this problem fix itself last year and surely the domestic hot water doesn't need the expansion vessel????

 

[durhamplumber]

Don't think the boiler came with a 7 year warranty although I did buy it from the Plumb Centre. Would the expansion vessel have a 7 year warranty????
How did this problem fix itself last year and surely the domestic hot water doesn't need the expansion vessel????

As far as I know,baxi duotec is 7 years,all parts warranty

 

[CBW]

I’m out.

 

[Peter Goble]

Chris, thanks for your advice and I am certainly not ignoring it and I appreciate it, but as an engineer (mechanical) my mind likes to investigate every option and cant fully understand how this issue can be intermittent if it is a component failure.

 

[terryplumb]

Don't think the boiler came with a 7 year warranty although I did buy it from the Plumb Centre. Would the expansion vessel have a 7 year warranty????
How did this problem fix itself last year and surely the domestic hot water doesn't need the expansion vessel????

The problem wouldn't fix itself ,but the symptoms may have changed.
I.e. you don't see such a pressure swing ( or didn't notice it) if expansion is accommodated elsewhere. For instance a radiator holding a largish quantity of air ,would act as a makeshift expansion vessel.

 

[Donald_diy]

As a customer. when was the expansion vessel last inspected or air charge topped up, there a serviceable item (as per the vessel maker) instructions .

Been there found out free warranty call outs/repairs onsite can be quickly converted to chargeable work if the lovely boiler is not properly maintained, annual safety checks are just that.

Over the years in different properties have had many gas combination boilers where pressure gauge needle will encounter differing travel during different varying demands, which is Ok as long as the vessel is properly air charged on a correctly installed boiler.

As already mentioned, care for the expansion vessel. They deserve the care

 

[Peter Goble]

Thanks everyone, I am now swayed to the expansion vessel.

 

[ianmcd]

It is an expansion problem , the vessel should be checked and charged on every annual service, but they very seldom are, if you havent had the boiler serviced every year then the warranty will be invalid

 

[Peter Goble]

Had a gas engineer round today, expansion vessel was own a tiny bit, re-pressurised, condensate trap emptied and still not working. He said he is pretty sure it is the pump, any thoughts before I spend hundreds on a new pump????