Little Clanger

Again, thanks, John Well I can definitely push the pin in the body in with finger pressure, although with difficulty, and the pin springs out again OK. The fact that it shuts down on '0' setting but then opens on even the frost setting suggests the valve is opening and shutting properly. I've just had a closer look, with a torch shining though the vents in the head. With the adjacent air temperature 15o, when the TRV is set on '2' (15o - 17o), the expanding capsule is still loose in the head - there is a small gap between the top of it and the fixed bridge that it bears on, and you can wobble it with a knife. I would have thought that, considering the open/shut temperature range for this setting, it would at least be bearing on the valve pin and possibly starting to push it in to shut off the flow. This sort of confirms for me that the head isn't seating down properly and so increasing the distance between the valve and actuator pins. I tried tightening the collar with grips, but it didn't make any difference. The weird thing is all the TRVs are behaving like this!

Thanks. They are new TRVs and valves. The pin in the valve does push in when you put finger pressure on it. And anyway, it shuts down OK, when set to '0'. The pin in the head moves when heat is applied (when removed), so it's expanding OK. The total movement of the pin is only about 10mm from shut to fully open, so presumably only about 2mm of movement for each progressive setting. It's as if the pin needs to be fractionally longer, or the head screwed down tighter to shorten the distance. I've only done the collar up finger tight for fear of damaging it. Perhaps grips would pull it in a little more. Anyway, thanks again

Thanks. Yes, discovered that!

Thanks for your suggestions. Think the head is on OK. On these, there is a female hex on the head that fits on a male hex on the body. The expansion vessel appears to work - I took the head off and ran a hair dryer over it and the pin in the head definitely moved. Thanks again

I've fitted Pegler Bulldog TRVs to all my radiators, but they don't seem to be responding to room temperatures. On '0' they shut off the flow OK, but on any other setting they come on regardless of room temperature. For example, with the radiator turned off, I left a thermometer (on a Horstmann room thermostat sender), adjacent to the TRV. I left the thermometer to settle, which it did at 15o. According to the Pegler information, the TRV should have opened at this air temperature when set at '2' (15o - 17o), however, it opened as soon as I got to the frost setting, '*', which is supposed to be 7o. The thermostatic heads are seated down properly and the locking ring is tight. I've tried changing the heads, but same result. Any ideas, or have I misunderstood how they are supposed to function?

I've fitted Pegler Bulldog TRVs to all my radiators, but they don't seem to be responding to room temperatures. On '0' they shut off the flow OK, but on any other setting they come on regardless of room temperature. For example, with the radiator turned off, I left a thermometer (on a Horstmann room thermostat sender), adjacent to the TRV. I left the thermometer to settle, which it did at 15o. According to the Pegler information, the TRV should have opened at this air temperature when set at '2' (15o - 17o), however, it opened as soon as I got to the frost setting, '*'. The thermostatic heads are seated down properly and the locking ring is tight. I've tried changing the heads, but same result. Any ideas, or have I misunderstood how they are supposed to function?

OK, so as a temporary measure, I've decommissioned the TS and installed a Willis heater. Actually works really well for our limited needs and very simple - both pump and heater are controlled by the same time and thermostat switch. Reflecting on the relative failure of the TS, I realised that a lot of heat was being 'lost' by convection (and possibly expansion), with the TS on the ground floor and the 6.5 metre run of uninsulated flow and return pipework on the first floor. As HeatGeek point out, this heat isn't lost to the house as it is within the thermal envelope, but it still meant that it was a loss of stored heat energy. In the mornings, the one open radiator was hot even though it is on the ground floor, and the pipework was hot all day. Possibly explains why the thermometers on the TS and the flow pipe rarely showed more that 60 degrees, even with the overnight thermostat at 75. Now I'm wondering if I could have retained more heat in the TS if I had tried to break the convection by sweeping the flow pipe from the top of the TS downwards before looping back up to the existing pipework, but not sure if this would work.

That's encouraging, John, thanks. Presumably that's with a monobloc ASHP Again, thanks. Great forum

Again, thanks. I can see your point, although I assumed electric radiators in a bathroom wouldn't be safe. Also, I'm reluctant to remove the wet system because eventually I'd like to have an ASHP. Much as I enjoy amateur plumbing and wiring, I assume installing an ASHP would be a step too far, so I'd need to take up a government grant, and I was told that to qualify you have to have no other source of heating (although I couldn't find this condition in the government blurb). I'd miss the woodburner as it gives us some independence from power cuts. So really I'm in a holding situation until I take the plunge. Anyway, thanks again for your help and advice. John

In practice, Nick, the TS isn't really working. Nearly all our heat needs are met with the Everhot and the woodburner, so heating up 250l of water overnight isn't such a good idea, after all. Especially as it loses temperature quite quickly once the CH is running and boosting with the upper immersion heater gives a slow response. When it comes down to it, we seem to just need about an hour in the evenings for the bathroom radiator (600x600 Type 22), and about a couple of hours in the mornings, during off-peak times. As a result I'm leaning towards your idea of an in-line boiler - much simpler and more flexible, and from my calculations, actually a bit cheaper than heating the TS. I've seen on the UFH section that people use WIllis heaters as a heat source. Do you think that would work as an in-line heater in my vented system with such low demands? Or do they require a larger volume of water, e.g., a small cylinder? PS. The noisy return seems to have sorted itself. Possibly trapped air that finally cleared. Silent running now willis.pdf

Thanks for all your help, John. The Stanley had a huge boiler, so that could explain the difference. A higher vent would be difficult, but not impossible, so I'll give it a try. Thanks again John

In that photo, the flow is from right to left, so hits the 22mm vent first (although of course the pump is on the return, so drawing through the flow rather than pumping). I gleaned the power data from the labels on the pump. Not directly comparable as the Trident is derived from 220v, the Grundfos 240v. The Trident draws more current (0.25 amps compared with 0.17), which at 240v gives 60W compared with 40.

Should have been more specific. The old Grundfos is a UPS 15-50. The Trident is a WRS 25/60-130, listed as a replacement for the 15-50.

OK, John, so the height from the pump to the water level on the F&E tank is 3.7m. By 'the pump head', I assume you mean the suction pressure of the pump. The blurb for the pump (a Trident) only says that the maximum head is 6m (presumably maximum pressure when pumping on the flow). The pump is set on the lowest speed, 1, although actual rpm aren't given, and I've a feeling it runs a bit faster than the old Grundfos. It uses a bit more power. With the glass of water test, the level stayed the same, but when the pump first started up - before I'd got the glass under the vent - water was pumped out of the vent a couple of times. Previously, we had a big Stanley solid fuel range, burning wood. Thanks John

Brilliant idea, thanks. Presumably a falling level in the glass means it's drawing air in? I did try stuffing a cork in the vent - temporarily - but that made no difference. Do I even need a vent now I don't have a boiler? Presumably any expansion in volume as the water heats up would be accommodated by the F&E pipe, since even if a thermostat goes, they have a safety cut-out?