Radiators not Heating Up

BUFF

the label says that it is an ecotec plus 615 - that is a system boiler.

plumb1_2

BUFF said:

the label says that it is an ecotec plus 615 - that is a system boiler.

Correct, I must learn to use my reading glasses more often, back to the £ shop.

tristanjourney

The cylinder does have a thermostat, but the previous picture didn't show it. I will attach a new picture. I also marked the two pipes that I found always hot, i.e., the red rectangle at the top left side of the picture.

When the gas engineer serviced the system early this week, he did check the hot water cylinder. I hope it should at least work properly?! It's a shame that he didn't catch this bathroom radiator issue, but I guess they just tick the box after checked the radiator is hot when CH is on, instead of check things when CH is off  

ThisIsWeird

Cool - the cylinder stat has been refitted.

Ok, the important bits are:

1 -The RETURN pipe to the boiler

2 -The FLOW pipe from the boiler

3 - An auto-by-pass. So that means your towel rail doesn't have to serve this purpose. Good.

4 - Motorised 'zone' valve. This is what opens to allow the boiler flow to go to the hot cylinder to heat it up. It is controlled by the programmer timing, and also by the cylinder 'stat. The former tells it when to open and when to close, and the latter will close it if the desired cylinder temp is reached.

5 - Motorised 'zone' valve for the CH. Again, this is told when to open and close by the programmer timer, and then by the wall stat.

6 - What the hell?! This is very bad plumbing, and looks badly DIYed. The pipe coming out t'top of t'tank is the hot water supply to the taps and showers (you can tell if the tank is 'hot' by grabbing that vertical copper pipe). That narrower plastic pipe has been added to provide a separate hot water supply to something - could you trace it, please, and find out where it goes?

ThisIsWeird

Ok, next thing is to get to know your motorised valves a bit better. Could you take a close-up photo of the No5 one, please?

Hmmm, interesting pipe there...

ThisIsWeird

See this pipe - the top arrow? It appears to be teeing off the boiler flow pipe before it reaches either motorised valve. That means that hot water will flow through that pipe whenever the boiler is turned on, regardless of whether it's for DHW or CH. Hmm, I wonder...

Can you trace where it goes? Does it have anything to do with the two 15mm pipes disappearing through the floor (the other two arrows)?

The other Q is, why does your boiler run when neither the CH nor the DHW are being called for? If the programmer says 'off', then the boiler should simply NOT be running. If the prog says 'on' for CH, but the wall stat says "This room is warm enough", then the boiler should not be running. If the DHW prog time says 'on' but the cylinder stat says "I'm satisfied - piping hot, me", then the boiler should not be running.

tristanjourney

Thanks for the detailed explanation! @ThisIsWeird

For the bad plumbing work you mentioned (i.e., arrow 6), I believe it is used for the shower pump. There is a shower pump in the loft. This is just my guess. Need to be onsite to confirm.

For the pipe that not go through any of motorised zone valve, I think it goes to the arrow in the middle. Again need to be onsite to confirm. How can I know if is used for the bathroom radiator or not?

I am not at the house at the moment, but I can probably find answers and take more pictures tomorrow.

I don't mind the bathroom radiator is on when either central heating or hot water is on, but the issue I see now is it is always hot and boiler seems always working. I turned off the boiler in the meantime, because I feel the system isn't working properly (I mean it seems functional but the boiler doesn't seem to know when to stop).

ThisIsWeird

It would make sense that the 'bad plumbing' goes to a power shower. That's ok. Just 'badly' executed! Not to worry about that.

If the towel rail is hot, then check to see if that tee'd pipe is ditto. And see if any other 15mm copper pipe is ditto-ditto - that could be the return from the towel rad.

As you say, if that towel rad came on only when either the CH or DHW was on, then fine - it would/could be a useful feature, and the towel rad could always be shut off/turned right down by using the manual valve on it. But the concern is that the boiler is seemingly running when it should not be.

If you turn the Drayton programmer so that both the DHW and CH are definitely 'off', then the boiler should not come on. If it does, then summat is amiss (like a motorised valve).

The Drayton has two indicator lights - check that these come on and go off as you select 'timed' or 'on' and then 'off'. If both lights are off, the boiler should not be coming on, regardless of the wall and cylinder 'stats.

The sequence of operation is:

The Programmer tells the CH and/or the DHW to come on, eg when it is 'timed' to do so. The indicator light(s) on the programmer should come on.

The programmer sends a live signal to the wall stat (if the CH is to be on) or the cylinder stat (for the DHW).

IF the room 'stat is 'calling for heat' - ie if the required temp is higher than the current room temp - then the wall stat will send that live signal to the CH motorised valve, for it to open.

Ditto for the DHW - if the water temp in the cylinder is cooler than that set on the cylinder stat (typically ~65oC), then the cylinder stat will send that 'on' signal to the DHW motorised valve - and it should open.

When a motorised valve opens fully, it sends the 'on' signal to the boiler so that it now comes on.

The boiler is the last item in the chain. The prog has to say 'yes', the stat has to say 'yes', and the valve has to say "I'm open!"

So, the programmer has a 'switch' in it, as do the 'stats, as do the motorised valves.

It does happen that motorised valves can fail after, say, a decade or so, and one type of fault can have it seized in the open and 'on' position. That can send an 'on' signal to the boiler regardless of the other devices are saying.

If you show us a close-up of the CH valve, we can guide you on what to look and listen for.

tristanjourney

If the towel rail is hot, then check to see if that tee'd pipe is ditto. And see if any other 15mm copper pipe is ditto-ditto - that could be the return from the towel rad.

Can you please elaborate this? I don't fully understand.

If you show us a close-up of the CH valve, we can guide you on what to look and listen for.

I'll do it tomorrow. Thanks again for the detailed explanations. Never learnt so much about those in my life 

ThisIsWeird

tristanjourney said:

If the towel rail is hot, then check to see if that tee'd pipe is ditto. And see if any other 15mm copper pipe is ditto-ditto - that could be the return from the towel rad.

Can you please elaborate this? I don't fully understand.

Since the towel rail is hot, it must be getting a hot supply. You've already pointed out the two BIG hot pipes at the top - these make sense, as they are the boiler's main flow and return pipes. What we need to find now are the pipes that are coming off these, and are supplying the towel rad

If you were to find that the tee'd-off pipe was also hot, and hot all the way to the floor, then that would almost certainly make it the culprit. And then perhaps you could find a similar pipe that is hot-ish, and that could be the return from the towel rail.

(It still wouldn't answer why the boiler is running when it shouldn't be, of course!)

By the same token, if the prog is 'off', and/ or the wall stat is 'satisfied' (ie, not calling for heat), then the CH motorised valve (the lower one) should be closed. That means the pipe exiting that valve from underneath it should also be cold. If it's hot, then summat is amiss.

Anyhoo, we can run simple tests to determine pretty well if it's working as it should.