All but one cold rads, but hot pipes & hot water, house Brrrry cold!

[MrRY]

It's a decent sized system, 8 rads upstairs, 4 down, the only rad that gets hot is the bathroom one. Glow-worm ultracom 38cxI I think about 10 years old I think has orange light panel with mode CH/off, temperature setting, pump inside casing. The boiler fires up and the temperature goes up nicely BUT:

The other radiators apart from the bathroom one all have hot pipes to them, but the radiators are barely warm at one end only. All rads except dining room one have TRVs which I have tapped the pins of and worked up and down. All rads are bled. The Honeywell thermostat with temperature dial is in the dining room and is set to 21C (room temperature is much colder than this).

Anything I could do to experiment/check/report back on? It's getting cold and I really don't want the place to freeze!

Help much appreciated if you can suggest anything! I have tools and a turbo torch and bits'n'bobs but little idea!

 

[jtsplumbing]

Possible that the pump is US , running very weak so water is not moveing.

 

[MrRY]

Bother. It had a new pump about 4 years ago (says my old Mum!). Would it help if I opened the lockshields? I just want to keep the place from actually freezing in the short term. I wonder whether there's a speed setting on these pumps? The pump seems to start with a swishing noise, but whether that's the impeller, air or kettling or normal I couldn't say.

Thanks for that, BTW.

 

[MrRY]

OK, I've just looked at this system again. The boiler is a Glow-worm Ultracom 30sxi.

After 24 hours since my last visit, the system was cold, boiler pressure only 0.3 bar (previously it was way over pressure I assume at 3.1 bar). I let in a bit more water, and it went up to 0.6 bar, and started heating. The temperature reading on the boiler panel went steadily up to 64C. The pressure, bizarrely (?), then read 2.2 bar.

So, I left the boiler on and removed all the TRV heads, to tap the pin lightly & repeatedly with a small hammer. The pipes, most of which had been warm to the TRV but NOT the rads went cold (except the one furthest from the boiler which was cold but became warm), then after a minute or two became warm again (except the one which became warm, which went cold again). No idea why. The rads (except the bathroom one) were all cold (but as I say pipes warm),

So I went around opening the lockshields. No dice. The bathroom lockshield was nearly closed, so I opened it a bit. No detectable change.

In the airing cupboard is a thing on the end of a vertical 35cm piece of 15mm copper. I suspect it is some sort of air vent. It had a black plastic knurled screw which I thought might be a bleed valve so I twiddled it. A brief hiss, then nothing (& no water).

There's another unknown thing on one of the pipes off the theree-way valve, that has a red plastic turnable cone with some sort of pressure valve in I guess, marked at 0.1 to 0.5 bar, set at 0.4 bar. No idea what that was. The 18mm on the 3-way valve side of that thing was hot. The other side was cold.

The three-way valve had connections A, B & AB, all hot. The pipe A which looks as though it goes towards the radiators has another run next to it (both 18mm) which could be a return. That was cold.

The three-way valve has a lever on it. This was loose and floppy. On other three-way valves I have seen, the lever has some resistance to movement, and can be hooked over a lug to keep it in one position. This lever was not spring-loaded, and would not hook onto the lug. No idea whether that's normal or broken.

The wiring is a mess, with chocolate block connectors joining wires, taped up with no-longer-sticky duct tape. The connections look OK though.

Well after all that, the radiators suddenly heated up. The one furthest from the boiler was not very warm, but then again all the lockshields were open.

I turned the boiler off again, and the pressure read 3.1 bar (a few minutes later 2.7 bar). I switched it on and off again and it stayed at 2.7 bar.

I have no idea what the cause of this is. It is most confusing.