No hot water, but heating is fine

[mortta]

Hello,

I have a glowowrm spacesaver-50 boiler in the kitchen, a hot water cylinder and 2 water storage tanks in the loft. (Gravity system)

Well on Sunday I replaced a radiator, by switching off the water supply from the mains and draining the whole central heating system.

All went well until the next days when the timer kicked in and the heating came on fine, but no hot water. I have drained the system twice and I've checked the cylinder and all pipes going in/out are cold.

The boiler kicks in fine, pump is working, not to sure if I have a 3 way valve or not. but since the radiator change we have been hearing a bit of whaling noise underneath the bathroom floor. I've used a spanner to knock a few of the pipes just in case of airlock, but still no joy.

Does anyone have any suggestion?

Much appreciated.

Mortta

 

[Softus]

How clean/dirty was the water that you drained from the system?

How dirty was the water that dribbled out of the old radiator?

Did the F&E cistern empty when you drained the system?

And when you refilled, did water empty nicely out of it and into the system?

 

[Dukie1977]

Hi there,

Do you have gravity hot water and pumped central heating?

You say you don't know if you have a 3-port valve - do you have any sort of valve?

Also is the bathroom radiator heating up?

Merry Christmas by the way

 

[mortta]

Yes, the water emptied fine, the water was initially clear and then black near the end.

Bathroom radiator is fine, yes I have a gravity hot water and pumped CH.

F/E did drain and then refill when I turned the mains back on. The speed of the refill was a bit slow, but it did speed up when I hit it with a pipe.

I have noticed that underneath a floor tile in the bathroom that I have 2 22mm pipes which are very hot. unfortunately I can't trace the pipes.

 

[Softus]

F/E did drain and then refill when I turned the mains back on. The speed of the refill was a bit slow, but it did speed up when I hit it with a pipe.

It's possible that you have a partial blockage, with insufficient water entering the system to form a gravity circuit.

It's also possible that you just have an air lock. Is there are a vent anywhere near the cylinder?

 

[mortta]

I can't see any vents near the cylinder but I did loosen one of the pipes connected to the cylinder and water came out. ( not the top pipe, but one that is 30 inches from the bottom of the cylinder)

I did want to check the F/E tank but it is sitting on rafters and is right up next to the roof in the loft.

 

[Softus]

Can you loosen the top cylinder connection (without risking making it leak permanently)?

 

[mortta]

Are you talking about the 22mm at the very top of the cylinder? or the other pipe that is connected to the heat exchange coil

 

[Softus]

Are you talking about the 22mm at the very top of the cylinder? or the other pipe that is connected to the heat exchange coil

The latter - the pipe at the top of the coil (usually the flow, but not always). If you get water out of it then unless there's a blockage there's no reason for water not to flow around the primary circuit.

 

[mortta]

Softus....

Will do, i'll try it tomorrow and get back to you, I've been on this problem all day. I need some sleep. Many thanks for your help so far.

I will post back tomorrow, I'd appreciate it if you can keep an eye on this thread and give me your response after I post my results.

Have a good night.....

 

[Paul Barker]

I did want to check the F/E tank but it is sitting on rafters and is right up next to the roof in the loft.

I had one recently warnign pipe demonstarted float valve needed attention. No access to loft, I mean the woman who had just moved in had got her woman odd job person to nicely board up plaster and paint the ceiling.

""why is it leaking" "because that's what happens they don't last forever, it happens to everybody I spend a lot of time in people's lofts"

"oh alright then I suppose if you must make a hole in my ceiling" So I made a hole stuck my head up, and I'd come out wrong side of cistern. Popped head back down made another hole calculating about where float valve side would be (cistern jacked right up to eves so no possibility of reaching float valve from wrong side). Blast, I came up where 4 pipes cross the joists. anyhow by removing the warning pipe I could squese my head (after removing glasses) and one shoulder between other pipes then other shoulder, then could do the job. That was a relief thought I might have to go in through the roof for a moment there.

Same woman knowing that I had to fit a radiator in one bedeoom had new carpet fitted first. When I got there to fit rad I said the "carpet will have to come up, though I'll do my best I can't make it look like this again perfectly fitted new, you might need to get your carpet fitter back". "do you have to lift the carpet? I'm so mad" to which I retorted "don't you get mad with me, I'm mad with you, you knew I had to fit a radiator and you've gone and got new carpet fitted, you should have waited" to which she backed down "oh know I'm not mad at you I'm just mad that nobody told me"

Thick or what?

 

[namsag]

Quite a basic fault after draining a gravity system . You have an airlock in the gravity circuit .Try running boiler on max with just HW on if that doesnt work it needs boiling up by removing boiler stat for a short time to shift it... Sometimes they will shift themselves after a few days