Glow Worm Space Saver: No CH, confusing system

[GettingOnWithItAll]

I’m visiting my mother’s bungalow and am short of time to investigate her CH not coming on, so can anyone help please?

The issues:
1. The very old system is confusing me as 2 of the rads are on with the hot water, the rest being as I expect under CH control.
2. The CH has stopped working and the system is different to the indirect system in my house that I’m familiar with.
3. I’m IMO a competent DIYer but no specialist plumber and my mother will have trouble dealing with plumbers/fitters without my finding out more first.

The system:
1. The kitchen-mounted boiler (see image) has ‘Glow Worm Space Saver MkII’ on the front and I can find nothing with any further info such as a model number or build date. It has a cold feed pipe from underneath and 2 pipes that are hot to the touch going vertically into the roof space.
2. The controller is a hard-wired Drayton Lifestyle with programmable times but no programmable temperatures.
3. The non-working rads all have supply and return feeds that go vertically in trunking to the roof space. Of the 2 rads on with the hot water, even in summer with the CH off, the kitchen one has the feed pipes going horizontally through a wall into a space below a raised floor section for the shower in the bathroom and the bathroom ones go into a false wall, to where I don’t know. There are no rad thermostatic valves.
4. There is no immersion tank, at least in the body of the house.

What I’ve tried:
1. I‘ve checked the controller, including changing it to a permanently on setting, to no avail.
2. I’ve searched for a manual but have been stymied as I don’t have a model number and the half dozen I’ve read have diagrams that don't match up with what I see.
3. The manuals suggest the boiler has separate HW and CH circuits with an inlet and outlet pipe for each, a total of 4 pipes, but I can only find 3 (one cold, 2 hot), but my attempts to explain this have come to nothing.

The long-term solution is to replace the whole system, but for now I just want to get it going, preferably whilst I’m here now as I don’t want to come back to deal with plumbers (it’s a long and expensive trip here).

Please help if you can.

 

[Hugh Jaleak]

Boiler, 2 pipes 'hot to the touch' are the Feed and Return for the system. The 'cold feed' is actually the Gas supply.

You are looking at, I suspect, a 'Fully Pumped' system, either on a 'Y' or 'S' plan, with 1 or 2 Motorised Valves controlling the flow of water through the system. Think you need to locate the Hot Water Cylinder, and chances are, the Motorised Valve(s) will be somewhere in the vicinity. I'd hazard a guess it's a 'S' Plan system, and the valve controlling the CH has failed.

The two Rads that work all year round may well be a bypass, an open circuit to provide a path for flow through the system at all times.

 

[terryplumb]

You must have a hot water cylinder ,possibly in the loft. Look for motorised valve/s near it .
Is there a wall thermostat for central heating ?

 

[GettingOnWithItAll]

Thanks.

You're right about the pipe. I got that wrong. I’d seen a gas supply pipe going to the gas control valve and one out upwards to the burner; the pipe that I thought was a water supply and had felt seemingly not going near the gas control valve does indeed connect to that valve.

There is a separate thermostat that turning to a high temperature made no difference. I’ve left it at a high temp to give the gods of plumbing chance to fix things overnight so that the CH comes on in the morning.

I’ll go up into the attic tomorrow morning and check out what’s up there. I can check if the pump runs and see if there’s a manual setting to move on the motorised valve, which will at least buy me some time.

 

[GettingOnWithItAll]

I think it’s the thermostat, a Honeywell T40, as twiddling it this morning suddenly got the CH working when leaving it at 25 deg didn’t. A new replacement was cheap and easy with a Screwfix a couple of miles away, so within a couple of hours I had a reliably functioning system.

I did poke my head into the attic to see a cylinder, but the piping and any valves were buried away under filthy insulation. With no working or protective clothing with me I decided to leave investigating the pipe set up for my next visit.

Again, thank you. Your help made a big difference.