Baxi 105E - CH only reaches 50 degrees - Genius required!

[Silvana]

Hi can anyone help as my heating engineer has come to a dead end. The heating on my boiler (Baxi combi 105E)only reaches 50 degrees which leaves the radiators warm but not working at full heat. The hot water is fine, it actually reaches the maximum temperature on the boiler of 70 degrees but the heating won’t go any higher than 50 degrees. I do not have radiator thermostats or a room thermostat and the pressure on the boiler is fine, as is the pump. The radiators have been bled and some of the radiators been taken off to check for sludge but they were clear so it doesn’t appear to need a powerflush, it’s just that the heating won’t go any higher on the boiler than 50 degrees (as per the display panel) when it should be able to reach 70 degrees. One of the radiators was also taken off to see if that improved the heating but it didn't. Has anyone got a suggestion as to what the problem can be as my heating engineer and I are at our wits end!


Thanks
Silvana
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[Hardy1]

have you had any new rads added on to the existing system?, has your engineer checked for trapped air? cause that is probably where the fault is, also has he checked for failty thermistors?, are the valves fully open?, would also recomend upgrading to trvs and adding a room thermostat.

 

[tipintim]

Thermister/potentiomitor ?

 

[Silvana]

Thanks just bought a thermistor so will get him to try that and also check for trapped air, thanks so much for the suggestions!

 

[Hardy1]

where did you buy the thermistor from?

 

[diamondgas]

The control knob spindle snapped is a possibility if the heating thermister is okay! The knob may be turning but it aint spinning the potentiometer on the pcb

Really need to be checking thermister resistances, bp's and modulation IMO

 

[arran197]

:iagree: I'd go with that. Or the knob hasn't been put on in the correct place on the potentiometer itself. Seen it quite a few times on Baxi products, Duo Tecs and other.

 

[Jonwells]

.Arran 197 may have hit the nail on the head, baxi control knobs can be fitted out of line, max on knob isn't max on circuit board potentiometer, I think the contol knods are fixed, so circuit board will need to be dropped out slightly, then turn with electrical screw driver to make sure when control knob is max then so is circuit board potentiometer. Jon

 

[moogwai]

Also check the filter inside the return valve....may stop water circulating.

Sent from my Desire HD using Tapatalk

 

[sparra1100]

have you had a new board fitted as the potentiometer nobs mite be in the wrong place then need to be back to zero when new board fitted or as above said broken spindles ave had that a couple of times