No hot water/Hot radiators

[camerart]

Hi,

I'm new here.

I needed to add a new radiator to an old system. Back boiler: Housewarmer 30/45. (Thorn?) Pumped heating, gravity hot water.

I also flushed it, cleaned the ball cock tank then bled it, flushed it and added inhibitor, then after a week or so, the hot water slowly started to get colder. I tried attaching a pump to points A-B which cleared a more brown water out. This failed, so I removed the hot water tank, and flushed at C and D through the coil then through the boiler, this cleared out lots of very black water. Once back together, it worked ok, till this morning. No hot water again. This time I suspect air. So I'll try bleeding again.

I would like to be satisfied once I get it going again, that this won't keep occurring, does anyone have any advice. I only want to get it working, and hope not to have to add extra pump etc.

Cheers, Camerart

 

[nysk2008]

Can we assume your rads are working?

 

[Millsy 82]

Sometimes it can take a month or 2 to get all of the air out of a heating system, Keep bleeding it and it should solve the problem.

 

[jtsplumbing]

Sounds like their is more sludge in system than you first thought, when you say that you flushed the system do you mean that you just draind it out ? have you had a cleanser in system ? (Fernox F5) or other make, no good puting inhibitor in if system still dirty, Where was you thinking of puting this other pump ??.

 

[heliotrope]

Drain down again and check out the cold feed connection where it joins at the
return pipe.

Cut the pipe just above the Tee. Clear any blockage that may be there. Put
back together with solder or compression coupler.

 

[Simon F]

you could try a wet vac on the vent pipe to try and pull any air lock out,
if that doesn't help then seems like a more intensive clean up required

 

[camerart]

Can we assume your rads are working?

Yes, rads are working.

 

[camerart]

Sounds like their is more sludge in system than you first thought, when you say that you flushed the system do you mean that you just draind it out ? have you had a cleanser in system ? (Fernox F5) or other make, no good puting inhibitor in if system still dirty, Where was you thinking of puting this other pump ??.

I have had 2 different types of cleaner in the system, flushed it with water about 4 times.

I hope I can get it running as it was, without adding a pump.

 

[camerart]

Sometimes it can take a month or 2 to get all of the air out of a heating system, Keep bleeding it and it should solve the problem.

I'm pretty sure there are no blockages, and you and 'simonf' are on the right lines.

I can hear air as I start the pump, and have been pushing water in and out from all orifices, all day. The air noises are getting less and the water is getting hot at the moment. There are still a few bubbles.

Looking at the diagram I posted, I notice the water coming into the system is on the same line as the vent. At point 'D' it goes down only. I'm sure this doesn't help.

Cheers, Camerart.

 

[camerart]

you could try a wet vac on the vent pipe to try and pull any air lock out,
if that doesn't help then seems like a more intensive clean up required

I did think of something like this today. A vacuum would most likely work.

In desperation, I also wondered if soap would foam the bubbles and get them to move round, (Just. a thought)

Cheers, Camerart

 

[camerart]

Drain down again and check out the cold feed connection where it joins at the
return pipe.

Cut the pipe just above the Tee. Clear any blockage that may be there. Put
back together with solder or compression coupler.

I have had the water tank off and flushed down each of those 28mm pipes. I'm almost certain there are no blockages.

Cheers, Camerart.

 

[Danv44444]

Try putting a magnet on the pipes, if it sticks chances are theres sludge in there.

 

[camerart]

Try putting a magnet on the pipes, if it sticks chances are theres sludge in there.

I tried this and no attraction, near the tank. After a couple of feet, the pipes change to steel. (It's working ok now after a lot of bubbling out)

Cheers, Camerart.

 

[camerart]

Yes, rads are working.

Sorry my mistake! The rads only work when the hot water is on.

jtsplumbing

You were correct. I attached a hose from the mains to various points around the system, and got loads more sludge out, plus a flush with sentinel.

Same as before, heating only when hot water is on. (there is no diverter valve) When the pump starts and stops I can still hear air, in the hot water tank I think.

Cheers, Camerart.

 

[JAP&H]

I needed to add a new radiator to an old system. Back boiler: Housewarmer 30/45. (Thorn?) Pumped heating, gravity hot water.

If as you say the system is gravity hot water, pumped central heating. Then you will only get heating when hot water is on.

Or if your programmer allows CH heating only you should get HW whether you want it or not.

 

[stevetheplumber]

to clear air from old gravity systems its often necessary to release it at the cylinder just loosen the nut on the top primary connection usually you'll get air then water so have a container under it or some old towels occasionally you will have to tapthe pipework to get it loose in the fitting dont undo the nut more than say one turn to do this

 

[camerart]

If as you say the system is gravity hot water, pumped central heating. Then you will only get heating when hot water is on.

Or if your programmer allows CH heating only you should get HW whether you want it or not.

I disconnected the boiler rad circuit, and flushed 1st through the boiler, and 2nd through the circuit, all clear and clean water. So no blockages.

I changed the programmer from a slipping clock mechanism to a digital one, with a choice of either or, but if you are correct, I should simply leave the timed water on and switch the heating on when I want. I wonder how long I would have kept trying. doh!!

 

[camerart]

to clear air from old gravity systems its often necessary to release it at the cylinder just loosen the nut on the top primary connection usually you'll get air then water so have a container under it or some old towels occasionally you will have to tapthe pipework to get it loose in the fitting dont undo the nut more than say one turn to do this

I have tried lots of different ways, but there is still air in there, so I'll try your method. Thanks.

I have attached a modified diagram of my system, this is how mine is, you will notice only one pipe fill/vent. Poor idea!!

Cheers, Camerart.

 

[JAP&H]

Hi camerart

Through all the draining and refilling you have stated the the radiators work fine so they are full of water taken from the F&E cistern. Good.

You seem sure that the problem causing a lack of hot water is an airlock on the flow or return to the cylinder. What makes you believe this is the case?

The motive force that causes boiler heated system water to rise up the flow to the cylinder is gravity. Hot water less dense than the cold in the return therefore circulation is achieved. Doesn't take a lot to restrict or block this.

Unlike your pumped CH you are unlikely to hear flow noise on a gravity system.

With boiler on HW only, are you able to trace the flow to see what distance (if any) the heat travels.?

 

[camerart]

Hi camerart

Through all the draining and refilling you have stated the the radiators work fine so they are full of water taken from the F&E cistern. Good.

You seem sure that the problem causing a lack of hot water is an airlock on the flow or return to the cylinder. What makes you believe this is the case?

The motive force that causes boiler heated system water to rise up the flow to the cylinder is gravity. Hot water less dense than the cold in the return therefore circulation is achieved. Doesn't take a lot to restrict or block this.

Unlike your pumped CH you are unlikely to hear flow noise on a gravity system.

With boiler on HW only, are you able to trace the flow to see what distance (if any) the heat travels.?

As the situation changed, I seem to have got some of my answers mixed up, sorry.

So, earlier there was a lot of air 'in the hot water tank coil?' each time I switched the heating pump on and off.

I tried stevetheplumber's suggestion of loosening the top tank pipe, and 1/2 filled a bucket, but it didn't clear it, perhaps not daring enough.

I then attached a garden hose, from a tap to the vent at the bottom of the 28mm pipes, and when it was turned on I held my fingers over the F and E cistern outlet and vent, till it built up too much pressure to hold, and I let it go, this blew out a lot of air, I repeated this 4 times, and got most of it out, till the tank overflowed. (Into the hot water cistern!!!!) This cleared most of the air out. I will see if the rest clears, for a while, and keep bleeding the system.

So now the hot water flow in the 28mm pipes is fine, and the water is getting hot. And if I turn on the pump all or any of the rads work.

So if as you say, the heating needs the water on to work, I think it's fixed. Just got to add inhibitor.

Thanks for all the help.

Cheers, Camerart.

 

[camerart]

If as you say the system is gravity hot water, pumped central heating. Then you will only get heating when hot water is on.

Or if your programmer allows CH heating only you should get HW whether you want it or not.

Hi,

I just found my long gone original programmer, see attachment. This verifies your reply. 3 way toggles shows. OFF/WATER/HEATING AND WATER .

Thanks, time for a HOT bath I think.

Cheers, Camerart.