Central Heating

Gazza_B

Hi,


I've bought a new house and have no idea how the central heating is meant to work.


At some stage a combi boiler has been installed, a Glow Worm Ultracom 30cxi. I'm having a few issues with it, mainly an F9 fault code relating to water pressure (or the water pressure sensor), however, for the most part I have hot water. I've tried to test the central heating and this doesn't appear to be functioning when I put the boiler onto central heating mode.


I'm not sure if it's related to an old dial Honeywell thermostat, that has a couple of "on/off" switches by it, that is on the wall. I'm not sure if this is a relic from the previous boiler, or would be connected to the more recent combi boiler? Or, would it be related to the regular F9 boiler fault?


Basically, I'm trying to avoid a giant cost for replacing the boiler and am unsure of the process I should follow to see where the fault(s) lie. I'm sure I'll have to call Glow Worm, or have an engineer come round to assess what's going on. Any tips would be welcome as to how I should approach this as I'm keen to avoid excessive call-out charges, and appearing on Watchdog or Rogue Traders soon after.


I believe the previous tenants had no issue with it (although they wouldn't be telling me if they had), but as I'm unfamiliar with the system I'm not sure if it's broken or I'm missing something simple which would save me unwanted expenditure. All I know for certain is I'll be wanting central heating before too long.


Thanks.

stator

If this isn't too obvious the simplest thing to ask is whether you have checked the pressure on the heating system? Does the boiler have a dial indicating the pressure?

Gazza_B

The pressure seems to cut off at about 1.7 bar. I turn it up to 2 bar (or slightly more) and the fault is resolved for perhaps a day or so before dropping again, and the boiler displays the F9 fault.


I think this error may be to do with the pressure sensor instead of an actual lack of water pressure.

Alex1983

F9 relates to water pressure or water pressure sensor, very common fault is they get abit dirty and cause a f9 fault, it will need replacing or cleaning, the pressure should be set at about 1.5bar.

This is probably unconnected to your no heating fault. Have you got a timer anywhere, may be hid in the back of a cupboard. Are the on off switches you say on the thermostat or just switches on the wall?

GrumpyDil

When you say you turn it up to 2 bar and it works for a few days before dropping again do you mean you add Water by the filling loop. If so and you need to keep topping up I'd say you are losing water which is what you will need to find. Off the top of my head two possible causes are a stuck pressure relief valve or pressure relief vessel and of course as you mention just leaks

You do need to identify where the water is escaping from and that once that is sorted will need to refill the heating system with relevant additives to prevent corrosion.

Gazza_B

There is an ancient Honeywell thermostat in the wall with two switches. It's so worn that I can't read what they're for, and can just about make out some writing indicating "on/off".
I wasn't sure if that thermostat, being quite dated, was a relic from the previous immersion heater that is no longer in use. I'll try the switches today to see if those get the central heating working. I've only found those switches after posting this thread or I would've tried them first.
The continued drop in water pressure is a concern, if it's due to a hidden leak somewhere, so I'll have an engineer come and investigate it and hope it's not too expensive to resolve (fitting a new sensor perhaps).
I'll let you know how I get in with the switches in the meantime.
Thanks again.