Radiators upstairs in dormer bungalow - Gravity system

[***Tom11***]

Gravity system.
2 rads and 1 towel rail.
Base of F&E tank to top of towel rail approx 300-400mm
Base of F&E tank to top of rads approx 800mm

All stone cold when heating is on, although the customer tells me that after the heating has been on for about 3 hours they do start to feel warm.

I have turned all trv's off to downstairs rads, leaving 1 towel rad with manual valves open (really didnt wana touch them)! to try and force the water up, if it will but no joy at all, pipework is just cold.

I've always thought you need min 900mm from base of F&E to top of rad for it to work ?

Anyone else had this ?

 

[Mastermixlee]

Personally I'd be advising to upgrade to a pumped system. As will Mean alot less headaches later on.

 

[Rob Foster]

Gravity system.
2 rads and 1 towel rail.
Base of F&E tank to top of towel rail approx 300-400mm
Base of F&E tank to top of rads approx 800mm

All stone cold when heating is on, although the customer tells me that after the heating has been on for about 3 hours they do start to feel warm.

I have turned all trv's off to downstairs rads, leaving 1 towel rad with manual valves open (really didnt wana touch them)! to try and force the water up, if it will but no joy at all, pipework is just cold.

I've always thought you need min 900mm from base of F&E to top of rad for it to work ?

Anyone else had this ?

hi Tom, the problem you have come accross is quite rare now, due to combis and system set ups. However I am an old fart
and others on here are even older.
1. was this system working b 4
2. has anything happened to cause the problem
3. beware do not get left holding the baby ...i mean give the customer a preliminary report about the obvious problem and duscuss it with them
4 then wevcan go,over your and their options.
Regards centralheatking

 

[rpm]

Personally I'd be advising to upgrade to a pumped system. As will Mean alot less headaches later on.

May sort the problem what about the cause of failure then?

 

[Mastermixlee]

Sorry read the post as if the rads were new to the system and the works had just been completed.

If they are new and not worked since install then could well be just an incorrect installation and. Not be piped in right.

If it's an existing system but has had works done recently involved a drain down then could simply be an air lock.

If it is an air lock then old school way was to removed temperature phial from boiler and let it heat up a bit more than usual (though does carry risks).

If it is a new system then you may find itll be easier for you, and possibly even cheaper for the customer (when considering time charged for trying to get working one gravity setup) to quote for pump installation.

Ultimately customers decision but I'd make them aware of the options.

Rob Foster hit the nail on the head with not being left holding the baby though. With those sort of jobs you're opening yourself up for callbacks any time it airlocks/cust adjusts a radiator if it ends up getting back to the same position. .. Of which likely they'll be expecting no charge as "you didn't sort it properly last time"

 

[***Tom11***]

As always, thanks again for the replies.

Its a pumped system with 3 port valve, does have a auto bypass fitted tho which is shut.
Think the loft conversion was about 8-9 years ago customers says and has always only ever been luke warm then. He just has put up with it.
He rang me a short while ago and said they have heated up again (luke warm tho) after heating has been on a couple of hours.
Crazy tho as said, earlier i had nearly all rads off and pipes didnt get warm !

 

[Rob Foster]

As always, thanks again for the replies.

Its a pumped system with 3 port valve, does have a auto bypass fitted tho which is shut.
Think the loft conversion was about 8-9 years ago customers says and has always only ever been luke warm then. He just has put up with it.
He rang me a short while ago and said they have heated up again (luke warm tho) after heating has been on a couple of hours.
Crazy tho as said, earlier i had nearly all rads off and pipes didnt get warm !

Dont go back yet it might well sort itself out, however if you do go back , charge another visit and shoot it up with main pressure...if you dont know what I mean ask away
Rob Foster aka centralheatking

 

[Mastermixlee]

Ah OK. If its pumped system already and pump condition OK, but rads still only getting luke warm, especially with it being only luke warm from install, I'd suspect either piped in incorrectly, pipe kinked or over application of solder blocking the fitting where it has been teed into.

 

[Mastermixlee]

Forgot to mention the other check which is remove radiator upstairs, connect up a hose on rad valve and open and see if you get flow come through. Repeat for other side. If water flow is only dribbling out one side (with system turned off) then you'll know its an issue with the pipework being restricted somewhere.

 

[SJB060685]

Rob what exactly and how exactly are you shooting this system up to mains pressure?

 

[Rob Foster]

Rob what exactly and how exactly are you shooting this system up to mains pressure?

Its really quite easy. Connect a garden hose from an outside tap onto the lowest drain off , mt cock secure with jubilee clips, open mt cock, then slowly open outside tap. go around the rads and bleed air out , lowest first, blip the pump on and off.
watch incase the F&e tank overflows out of the wall pipe.
so you shoot the system up with mains water pressure. most air locks give up this way. stopping is the reverse ..close bleed valves on rads, switch off outside tap, close mt cock, take temporary cinnections apart. If younthink ur system is sludged up, close off the valves to the boiler 1st send mains pressure in and out frim a drain off opening and closing rads off in turn. put your outgoing hise onto concrete or the road then you can see what Rubbish comes out
and if there is any chemical in the water ...the wriggly worms come out, go bonkers and die
any more questions no problem
centralheatking

 

[SJB060685]

Thanks. That’s as I thought, only wasn’t sure wether you were blanking vent and cold feed

 

[Chuck]

put your outgoing h[o]se onto concrete or the road then you can see what **** comes out

IMO, old CH system water needs to go down a foul drain not somewhere it can get into the ground. If you want to see what comes out, use a bucket as an intermediate stage. Old CH system water stains concrete, poisons fish, kills worms and plants, etc.

 

[Rob Foster]

IMO, old CH system water needs to go down a foul drain not somewhere it can get into the ground. If you want to see what comes out, use a bucket as an intermediate stage. Old CH system water stains concrete, poisons fish, kills worms and plants, etc.

I quite like the smell and taste
centralheatking