Baxi 80e combi. HELP!!!

[scoobyblue]

I have a baxi 80e combi about 7 years old.The heating works fine but hot water not.When i turn on the h/w tap it runs hot then cold,hot then cold . The burner activates for about 20-30 secs then goes out,it does not modulate.The diverter valve was checked and seams to be operating as it should.Now and again i have to top up the heating circuit as the pressure drops slightly. Had the same problem around 5 year ago and the dhw plate heat exchanger was changed and gas pressure adjusted.has anyone got any ideas what is wrong?

 

[Agile]

It sounds just like the plate heat exchanger being blocked again.

Tony

 

[scoobyblue]

no matter where the hot water control is the temp leds light up right up to 80 degrees.

 

[petit_pablo]

Blocked again then. The heat from main heat exchanger is backing up from the plate heat exchanger. Thats why the temp guage goes all the way up to 80

 

[scoobyblue]

could i add a sludge remover to the heating circuit to clean the plate heat exchanger then drain down and add an inhibitor or do i have to remove and clean?

 

[nogoodatfaultfinding]

could i add a sludge remover to the heating circuit to clean the plate heat exchanger then drain down and add an inhibitor or do i have to remove and clean?

Best and easiest solution is to get a new Plate heat exchanger.

They cost rougly £120.00 + Vat and its a ten minute change, bite the bullet and get a Pro.

 

[scoobyblue]

If i just fit a new one wont it just block up again.I thought if i add a sludge remover and drain it would help solve the blockage problem.Would fitting a Magnaclean afterwards help?

 

[Blooflame]

I would ensure the max and min burner pressures are correect before deciding that you need a new heat exchanger. So many things it could be really. If you are not Gas safe I'm sure your engineer will be able to check.

 

[nogoodatfaultfinding]

I would ensure the max and min burner pressures are correect before deciding that you need a new heat exchanger. So many things it could be really. If you are not Gas safe I'm sure your engineer will be able to check.

Hes wrong its the heat exchanger.
Turn your nearest tap on just enough to fire the boiler and if it stays hot theres your fault.
Youre Hot water Heat Exchanger has absoloutly nothing to do with your central heating side or you would have been drinking inhibitor since the day it was fitted.
GET A PRO!!!!

 

[chrisdixon85]

I would ensure the max and min burner pressures are correect before deciding that you need a new heat exchanger. So many things it could be really. If you are not Gas safe I'm sure your engineer will be able to check.

 

[nogoodatfaultfinding]

I would ensure the max and min burner pressures are correect before deciding that you need a new heat exchanger. So many things it could be really. If you are not Gas safe I'm sure your engineer will be able to check.

Do this and you will pay a call out for nothing, unless the gas valve has been changed recently and not correctly set however i would be suprised if the boiler is still on the wall if this is the case.
Gas valves are factory set on these boiler and as i stated unless its been touched its very rare they will move out of Max/Min Range!!

 

[scoobyblue]

Turned on the nearest tap to boiler just enough for it to fire ,water got hot but the flow reduced to a trickle. I also noticed the pressure gauge increased and there was a rushing water sound coming from the boiler.Turned off tap and pressure gauge dropped. There has been gas works in the street replacing gas mains ,could this have caused a problem?

 

[nogoodatfaultfinding]

Turned on the nearest tap to boiler just enough for it to fire ,water got hot but the flow reduced to a trickle. I also noticed the pressure gauge increased and there was a rushing water sound coming from the boiler.Turned off tap and pressure gauge dropped.

Guess what mate its your Plate Heat Exchanger (although with your new found diagnostic it could be your expansion vessel just needs charging).
Avoid this nonsense with Min/Max ratings (nothing like trying to scare someone).
As stated before this has nothing to do with flushing, inhibiter, cleanser or anything else of this ilk.
Get a local in to change it and jobs sorted.

 

[scoobyblue]

when the boiler is cold can i close off the heating flow and return valves and drain the boiler from the boiler drain point (not relief valve) and check the pressure in the expansion vessel?

 

[scoobyblue]

did as above . cleaned out h/e (until i can afford a new one) with pressure washer,checked expansion vessel (low - no air) recharged.Refitted h/e ,repressurised, nice hot water again. VERY BIG thanks to nogoodatfaultfinding.