Question about Gravity Fed Water/Heating
Discussion
My In-laws moved into a place earlier in the year that has a gravity fed system, probably 1980's ish. They had a combi before as do we.
Currently their system to get heating needs to have the hot water on as well. They can have hot water without heating. The controller has two separate controls for heating at water but trying the heating without hot water at the same time the boiler doesn't fire.
Is that normal? I seem to remember my parents many moons ago had to have hot water if they wanted the heating on.
The in-laws seem to think they are wasting money because they have this tank of hot water sitting there that they don't use ( they also have the room stat set at 25C but that's another thing.. I have tried to tell them that it's not constantly being heated - only when it cools off too much.
The immersion heater sprung a leak this week - cue emergency call out on Saturday evening - that'll be me then, why did they wait 2 hours from noticing water running down the walls though! Anyway turned off their hot water until I could fit a plug in place of the immersion yesterday,
It's raised the we want to get the boiler replaced for a combi again despite us telling them that's £2500 probably. They aren't that flush.
I was going to move the tank thermostat up the tank and maybe knock it back a few degrees to see if they notice a difference. I think they might then realise they are actually using the hot water when the shower runs cold
Currently their system to get heating needs to have the hot water on as well. They can have hot water without heating. The controller has two separate controls for heating at water but trying the heating without hot water at the same time the boiler doesn't fire.
Is that normal? I seem to remember my parents many moons ago had to have hot water if they wanted the heating on.
The in-laws seem to think they are wasting money because they have this tank of hot water sitting there that they don't use ( they also have the room stat set at 25C but that's another thing.. I have tried to tell them that it's not constantly being heated - only when it cools off too much.
The immersion heater sprung a leak this week - cue emergency call out on Saturday evening - that'll be me then, why did they wait 2 hours from noticing water running down the walls though! Anyway turned off their hot water until I could fit a plug in place of the immersion yesterday,
It's raised the we want to get the boiler replaced for a combi again despite us telling them that's £2500 probably. They aren't that flush.
I was going to move the tank thermostat up the tank and maybe knock it back a few degrees to see if they notice a difference. I think they might then realise they are actually using the hot water when the shower runs cold
Could be the switch in the valve for the the heating, what sounds like is happening is when it calls for heating the switch on the control valve is not starting the pump, but if you call for hot water the pump runs and the heating works, both valves open hot water pumping around the hot water and heating systems, unsure why it doesn't stop when the tank is up to temperature unless it had been turned up to max or pulled slightly off the tank.
PRTVR said:
Could be the switch in the valve for the the heating, what sounds like is happening is when it calls for heating the switch on the control valve is not starting the pump, but if you call for hot water the pump runs and the heating works, both valves open hot water pumping around the hot water and heating systems, unsure why it doesn't stop when the tank is up to temperature unless it had been turned up to max or pulled slightly off the tank.
It does stop when the tank is hot, trying to convince my mother in-law that's the case is the challenge, she thinks she has this massive tank ( It's quite new with lots of insulation on it and is actually quite small ) full of hot water being heated all the time.I do also wonder if at somepoint it had a control that only allowed HW or HW+CH and has had a different controller put in but no other changes ( wiring) to allow it to work with only CH.
SS2. said:
No, it isn't normal.
We had similar a few years ago - from memory, it was the motorised head on the zone valve for the heating circuit which wasn't letting the boiler know when it was open. Result = boiler didn't fire up when just heating was being called.
Cheers I think it's a 3 port motorised valve, I'll have to take my multimeter round and see what it's doing under different states. We had similar a few years ago - from memory, it was the motorised head on the zone valve for the heating circuit which wasn't letting the boiler know when it was open. Result = boiler didn't fire up when just heating was being called.
I suspect they won't want to get a professional in to look at it, seem that person is me at the moment..
mickmcpaddy said:
If its gravity fed there won't be any valves, the water control fires the boiler and the CH control/thermostat runs the pump only.
If it has valves then its fully pumped.
Our system used to be gravity fed, around 8 years ago it was converted to pumped. The boiler wasn't changed.If it has valves then its fully pumped.
blade7 said:
mickmcpaddy said:
If its gravity fed there won't be any valves, the water control fires the boiler and the CH control/thermostat runs the pump only.
If it has valves then its fully pumped.
Our system used to be gravity fed, around 8 years ago it was converted to pumped. The boiler wasn't changed.If it has valves then its fully pumped.
We've a gravity fed hot water, pumped central heating.
First year we were in (from June), we used the hot water with no problem, then come winter we started to try and use the heating without the hot water on and found it wouldn't work.
We had BG out to look at it, and after much confusion the bloke called his more experienced mate who confirmed that for the heating to work, the hot water also has to be on.
The controller was reconfigured accordingly and all worked well. If we hit the CH button now, both water and central heating indicator lights come on.
No idea how long it had been incorrectly setup.
So in brief, yes the hot water should come on when the heating is on.
First year we were in (from June), we used the hot water with no problem, then come winter we started to try and use the heating without the hot water on and found it wouldn't work.
We had BG out to look at it, and after much confusion the bloke called his more experienced mate who confirmed that for the heating to work, the hot water also has to be on.
The controller was reconfigured accordingly and all worked well. If we hit the CH button now, both water and central heating indicator lights come on.
No idea how long it had been incorrectly setup.
So in brief, yes the hot water should come on when the heating is on.
Ledaig said:
We've a gravity fed hot water, pumped central heating.
First year we were in (from June), we used the hot water with no problem, then come winter we started to try and use the heating without the hot water on and found it wouldn't work.
We had BG out to look at it, and after much confusion the bloke called his more experienced mate who confirmed that for the heating to work, the hot water also has to be on.
The controller was reconfigured accordingly and all worked well. If we hit the CH button now, both water and central heating indicator lights come on.
No idea how long it had been incorrectly setup.
So in brief, yes the hot water should come on when the heating is on.
The older mechanical timers had interlocks on the back so if you moved the CH slider the HW one moved with it but if you moved the HW slider it moved on its own, you could move the interlocks out of the way if you were fully pumped.First year we were in (from June), we used the hot water with no problem, then come winter we started to try and use the heating without the hot water on and found it wouldn't work.
We had BG out to look at it, and after much confusion the bloke called his more experienced mate who confirmed that for the heating to work, the hot water also has to be on.
The controller was reconfigured accordingly and all worked well. If we hit the CH button now, both water and central heating indicator lights come on.
No idea how long it had been incorrectly setup.
So in brief, yes the hot water should come on when the heating is on.
Similarly the electronic timers usually have a little switch on the back for gravity or pumped, so if you press the CH switch it automatically switches on the HW.
mickmcpaddy said:
The older mechanical timers had interlocks on the back so if you moved the CH slider the HW one moved with it but if you moved the HW slider it moved on its own, you could move the interlocks out of the way if you were fully pumped.
Similarly the electronic timers usually have a little switch on the back for gravity or pumped, so if you press the CH switch it automatically switches on the HW.
It's an electronic timer I've got with (from memory) 4 sliding switches which were not configured correctly.Similarly the electronic timers usually have a little switch on the back for gravity or pumped, so if you press the CH switch it automatically switches on the HW.
All I can think is that anyone using the system prior to us had the hot water on constantly and so never hit the issue.
Had the same fault on our system.
Google - Honeywell 3 way valve.
The valve has 3 positions, hot water, central heating and both. It's an old technology, synchronous motor, with spring return. The motor runs open, stalls by removing a 'phase' to hold position, and returns on the spring action when power completely removed. There are a couple micro switches within the mechanism for position. Basically it sticks. Dead easy to prove, take the cover off and you can see the spring. With mine touching the valve mechanism allowed the spring to overcome the stick resistance and run shut, hot water position. If that's all that was being called from the controller.
Now the bad news, they are not cheap, £95, and I had to drain the system and put another union in to allow the valve to be replaced without bending and forcing existing pipe work or tank.
Cured the problem with no issue.
Hope this helps, good luck.
Google - Honeywell 3 way valve.
The valve has 3 positions, hot water, central heating and both. It's an old technology, synchronous motor, with spring return. The motor runs open, stalls by removing a 'phase' to hold position, and returns on the spring action when power completely removed. There are a couple micro switches within the mechanism for position. Basically it sticks. Dead easy to prove, take the cover off and you can see the spring. With mine touching the valve mechanism allowed the spring to overcome the stick resistance and run shut, hot water position. If that's all that was being called from the controller.
Now the bad news, they are not cheap, £95, and I had to drain the system and put another union in to allow the valve to be replaced without bending and forcing existing pipe work or tank.
Cured the problem with no issue.
Hope this helps, good luck.
mickmcpaddy said:
If its gravity fed there won't be any valves, the water control fires the boiler and the CH control/thermostat runs the pump only.
If it has valves then its fully pumped.
This, its also common to have the bathroom rad on the gravity circuit, so when you heat water in the summer, the bathroom rad gets hot also.If it has valves then its fully pumped.
Gravity fed is a very simple set up.
Alucidnation said:
It depends of you have the satisfied wire connected.
Many earlier systems were HW or CH+HW.
+1 I would check this first. Sounds as though you don't have a gravity CH system but a fully pumped system with a Y Plan valve.Many earlier systems were HW or CH+HW.
There was also a W plan system which had priority hot water, so the radiators wouldn't heat up until the cylinder thermostat was satisfied. I doubt you have this set up.
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