Luke warm water coming from my BAXI INSTANT 80HE COMBI

[amjberry]

Hi there,

I recently had an issue with my DHW Pressure Diff Valve, whereby the thrust plate had rotted away. Unfortunately BAXI don't sell that as in individual part, only the diaphragm, so I had to buy a new valve. This solved that issue, however now I only get luke warm water through all my hot tops, be it sink, bathroom, bath or shower, yet the control panel shows the green light constantly lit for hot water and the temp climbing to 90F. The pre-heat temp is at a good high temp but then goes cold and quickly back to a just above luke warm temp. Any ideas ?? I'm thinking thermostat ?? Any ideas would be greatly received.

Thanks
Adam

 

[Gordon T]

DHW Pressure Diff Valve? Never heard of it. Are you meaning the diverter valve? Does the water come out at a higher temperature if you decrease the flow at the tap?

 

[diamondgas]

Do you find your radiators heat up when the hot water is on? If its only happened since you replaced the water section I'd be looking at something you may have disturbed! It was just the front water "diff valve" you replaced yeh?

 

[jtsplumbing]

You may have a dirty plate heat exchanger.

 

[REDSAW]

turn the pre-heat down to zero/off and see what you get?.

 

[1millwall]

your pr heat is probably stuck on. when you run the tap the boiler will fire the go out and water at tap stays cool. its the valve on the pipe to the vessel. the pin may be stuck in, worth a look.

 

[gaspastemania]

arnt you supposed to be gsr when working on boilers??

 

[amjberry]

@Gordon T - Yes it does, when I decrease the flow the temp is back to the correct level. Now the million dollar question, is this expensive ??!

 

[Gordon T]

Sounds like the plate heat exchanger could be getting dirty. Also your water flow rate may be too high. Get someone out to have a look at it. I went to one yesterday with the same problem. Turned out to be someone had thrown their boots into the cupboard with the meter in it, and accidentally knocked the ECV over a bit so the boiler was undergassed. You might find its a cheap fix as your boiler is working but just not up to the mark. If your radiators start to get hot when running the hot tap, the diverter valve is passing and you will need to have this replaced.

 

[amjberry]

The radiators don't get hot when running the hot tap, so hopefully the diverter valve is fine, so looks like the plate heat exchanger as the gas meter is outside.

Thanks very much for this - much appreciated.

 

[Poxi]

Hi there,

I recently had an issue with my DHW Pressure Diff Valve, whereby the thrust plate had rotted away. Unfortunately BAXI don't sell that as in individual part, only the diaphragm, so I had to buy a new valve. This solved that issue, however now I only get luke warm water through all my hot tops, be it sink, bathroom, bath or shower, yet the control panel shows the green light constantly lit for hot water and the temp climbing to 90F. The pre-heat temp is at a good high temp but then goes cold and quickly back to a just above luke warm temp. Any ideas ?? I'm thinking thermostat ?? Any ideas would be greatly received.

Thanks
Adam

What was the part number of the part you replaced..Did you replace PDA 248728