air getting into heating system

[portlaire]

Hi, My home place (which is a very old house) is having a problem with the heating system. I am also looking for any suggestions on efficiency improvements.
We have a stanley (originally solid fuel) cooker in the main living area which has the oil burner. The hot water cylinder is quite close to the cooker. There are two loops of radiators (5 rads on each) T'd off from the inlet to the cylinder coil. These two loops both come back to the circulation pump and the circulation pump is then T'd into the outlet from the cylinder loop (hope this makes sense). The rads are not getting very hot and when we try any adjustment of temp or pump it normally has the effect of causing water out the expansion pipe and somehow air getting into the system.
One thing that may be at fault (not sure) is that one of the rad feeds leaves the cyclinder and goes vertical into the attic it then goes across the attic and drops vertical to the rad loop. Could this vertical fall to the rads for the hot water be pushing water out the expansion pipe instead or should the pump pull the water around anyway.
My other query is on the coversion units? are these efficient, what would my other options be. The cooker is also used for cooking and heating the living area. (I have lots more questions on this system regards stats etc. - but I think I have enough questions here for now).
Appreciate any help.

 

[DavyJones]

Does the stove work on natural cirulation?

Does a pipe stat control the pump?

You have a design flaw on the system, this would be down to the position of the pump. Hence it pumps water up either the cold feed or expansion pipe, this causes air bubbles to enter system.

You could fit automatic air vents on the highest point of system I.E where the pipes run across attic.

It is hard to advise without seeing set up, We seem to fault find alot and it is usually a slight adjustment that has the system running right.

nine times out of ten the pump is incorrectly positioned on system.

 

[portlaire]

Hi Davyjones,
It's a stanley cooker and it has a pump on the radiator circuit. The pump is on the return before the hot water cylinder, the output from the pump Tees into the output return from the cylinder to the boiler (i.e. the output from the coil in the cylinder is piped back to the cooker boiler, the output of the pump is tee'd into this same pipe). The pump is controlled by a pipe stat.
There are two pipe stats, the boiler stat turns the boiler on once the pipe goes below temperature X, the pump stat turns the pump on once the pipe goes above temperature Y. I think it is done like this so that cold water is not piped around the rads i.e. it only starts pumping around the rads once the pipe gets above temp Y. So from cold the boiler would come on (pump would be off) until temp reaches Y at which point the pump would start. Once the boiler stat reaches temp X the boiler would turn off, pump continues running until temp drops below Y. I'm not sure that this is the conventional way of using stats. Both stats are on the same pipe, the feed from the boiler to the coil in the cylinder.
The water does seem to be going out the expansion, I did a little experimenting and it only seems to be a problem when I am running both rad circuits, if I turn off circuit 1 then I don't appear to have the problem with air (the circuits are connected in parallel, fed from the output pipe from the boiler and both return to the pump).
Any help would be greatly appreciated. I would like to get a plumber to look at this for me but I'm not overly confident with the ones that I know of.

 

[irishlinks]

I would like to get a plumber to look at this for me but I'm not overly confident with the ones that I know of.

I know what you mean! What kind of training or qualificaion do you need to call yourself a plumber in Ireland? The plumber that installed our heating system has had to be called back a few times to fix things - but I think he hasn't a clue really. We have rads not working , others that need bleeding every week , water coming out the expansion pipe on a regular basis. I need to find a proper plumber who knows what he/she is doing.

 

[DavyJones]

Hi Davyjones,
It's a stanley cooker and it has a pump on the radiator circuit. The pump is on the return before the hot water cylinder, the output from the pump Tees into the output return from the cylinder to the boiler (i.e. the output from the coil in the cylinder is piped back to the cooker boiler, the output of the pump is tee'd into this same pipe). The pump is controlled by a pipe stat.
Any help would be greatly appreciated. I would like to get a plumber to look at this for me but I'm not overly confident with the ones that I know of.

Sounds like it is natural circulation.

Circuit 1 is where the problem is. When its zone valve shuts down it is preventing the pump from sending water up the expansion pipe. Should be an easy fix once exact cause is found. It may just need a slight adjustment on pipe work, not for the diyer.

If you post your area, someone may recommend a good plumber.

 

[portlaire]

DavyJones,
Thanks for the reply. I don't know what you mean by natural circulation, is the pump not used for circulation? The rads are all on a single level (bugalow). I'm not sure if the pump pushes the water or pulls the water around, which would be the usual for this system. I did some more experimetation and when any one of the two circuits is used the system works fine, if both are turned on the cooker gets noisey I think due to air in the pipes and water comes out of expansion pipe.
I think water should be able to go up the expansion pipe whether one of the circuits is switched off or not, the expansion pipe is tee'd off the pipe feeding the coil from the burner.
I'm still sceptical about the way in which the pipe work for one of the circuits is layed, even though all rads are on the same level, the feed rises vertical from the hot press runs horizontally across the ceiling and then drops vertically to the first rad on the circuit (the return is layed similar). Is it possible that instead of the water dropping vertical down to the rads that it is easier for the pump to drive (again I'm not sure if the pump pushes or pulls) it up the expansion pipe?
I live in south Laois about 10 miles from Carlow town.

 

[DavyJones]

I have long since tried to make sense of some installations. I had to fault find on a similar case recently, only that in my case it was a triple system, heated by two stoves and a range. It had never worked right (installed by other)

It took a while to trace all pipe work and figure out why they did what they did. there are so many varibles, in some cases it is as simply as changing position of cold feed on system or turning a pump around. It normally takes longer to figure out what is wrong than to fix.

Basically you will need to get a good plumber in because as I said there are just too many varibles.

In your case it sounds like the pumps (when they both activate) are working against each other and maybe Non return valves (NRV) are being closed when they should be open. Again it could be many things.

Good Luck.