Glowworm hx24 doesn't seem to be at full power

[sotal]

We've just had British gas fit smart meters this morning and this afternoon they've fitted the hive smart thermostat.

They left the heating running when they left but 15 minutes or so later I felt like the house want warning up so I went to check the boiler and it had F22 on the display. I reset the boiler and it kicked back into life at full power until it reached 37*C but then it dropped to a quieter setting, initially it list a couple of degrees but it is now slowly rising but it is taking an age to get the house warm.

The boiler is set to the maximum temperature.

The f22 seems to suggest low water pressure but I can't see why anything done would affect that?

The previous system had a danfoss programmer which the hive receiver replaced on the same back plate. The previous system then had a towerstat wireless stat which had the receiver wired in. This has now been cut and removed.

I can't think of anything that would have affected it to make it run at half heat (or less!)

Any ideas before I phone British gas!?

 

[lightning]

Check pump is working or weak pump

 

[CBW]

It also suggested that there could be a wiring issue with thermistors, it might be as they’ve wired the hive in, that they’ve accidentally pulled a wire loose. Usually a low pressure fault can’t be reset. Did you actually check for low pressure?

 

[snb]

Hxi is a heat only so no pressure sensor. But it could give f22 if it doesn’t detect enough or too greater temp diff when it first fires. My bet would be pump speed down.

 

[lightning]

Make sure there’s water in header tank and cold feed is not blocked

 

[CBW]

Hxi is a heat only so no pressure sensor. But it could give f22 if it doesn’t detect enough or too greater temp diff when it first fires. My bet would be pump speed down.

How would it work on a sealed system though?

 

[Gasguru]

With many Vaillant Group boilers F22 can be a default error code for several conditions...where there is no pressure sensor fitted the error might
be given if the temp across the heat exchanger doesn't fall between certain limits.

 

[snb]

How would it work on a sealed system though?

same as with vented system. the boiler won't know about! or you would use an sxi boiler which is a system boiler.

 

[ScottishGasMan]

How would it work on a sealed system though?

Heat onlys (open or sealed f22 is no increase in temp detected on flow pipe on start up)

Systems and combis its low pressure as senses by the pressure sensor

 

[CBW]

same as with vented system. the boiler won't know about! or you would use an sxi boiler which is a system boiler.

I suppose I’d use either?