Puzzling Heating System Problem.

[RiverSide]

Hi All,

I have a bit of a plumbing puzzle you might be able to help me figure out; I can send an attached drawing of the system in my in laws home to anyone who might be able to help.
They used to have a separate hot water tank in the attic but it was replaced by a plumber a few years ago with the current system, it has me driven mad.

I replaced a rad for them, and shut off the water to the system as my step father said he normally would, I drained the system at the boiler as he said he normally would.

When the water had stopped, I removed the rad, it was the last rad down stairs on the system and I just capped the pipes close together rather than rip up the floor all the way back to the next rad and the second thing I did was I fitted a new double rad farther back the system in the same spot as an older single one.

The old plumber had disconnected their back boiler a few years back but rather than remove the built in furniture and concrete floor and cap the pipes the lazy bugger stuck some plastic pipe into the line to make a loop, at the same time he took out their hot water tank in the attic and place in a expansion vessel (CIMM 18 ltr EXE CE).

I also found a leak on a buried pipe so I fixed that and left all the new fittings exposed for the weekend to make sure leak free. My father in law said that the system refills itself after a while so I thought it must be an automatic top up sealed system, no worries says I. The rad's all heated and hot water came from taps and the rad’s bleed so off I went.

The leak I had discovered didn’t seal up fully so back I went after 2 day and did a job on it, I drained the system again and a bit of swearing and grunting later I stopped the leak fully and filled in the pipe channels in the floor with sand and sealed the floor with screed.

Then the doubt started. Where was this auto top up valve located?, I went back for another look as the hot water line had air locked on them and after freeing up the lock and restoring water I traced the whole system that I could find, now I am completely freaking out as I cant for the life of me understand where the hell new water is getting into a system that I have drained twice in the last week, I really want to add some inhibitor and get around to balancing the rad’s fully, but I am completely lost now and tearing my hair out.

SO a very long winded first post and thanks for taking the time to read it but questions for you all, please.

1. What type of system am I looking at?
2. Where is the top up valve?
3. Am I after capping a pipe I shouldn’t have?
4. If I had made a mess of it how in god’s name does the heating still work?
5. Why did I ever agree to do this job for them?

I know its hard to explain without seeing a drawing.

 

[davidoco]

.................... in a expansion vessel (CIMM 18 ltr EXE CE).

........... My father in law said that the system refills itself after a while so I thought it must be an automatic top up sealed system, ....


Where was this auto top up valve located?

SO

In or just under the casing of the actual gas (I assume) boiler is where you should find the filling valve with gauge - although I don't know how you got any work done without shutting it off before removing rads.

 

[RiverSide]

Thanks for the reply Davidoco.

The boiler unit is a firebird popular 120 c/w riello oil burner. The house water is taken from a well with a sunken local pump and passes through a large domestic pressure set which have membrane filters and sand filter and an accumulator. Switching off this set stops water going to the house so no fresh water was available to refill during the job. The fresh water is pumped to the main taps and then up to the attic storeage tank.

Normally I would have shut off the main stop cock but in this case I just shut down the pressure set.

I cannot find any sign of a filling loop, may I send you a drawing of the system please for a once over?

 

[davidoco]

Not necessary to send a drawing. I'm accepting here that you have a closed system and that 18ltr expansion vessel is used for the heating.

The filling point has to be somewhere so all you can do is start at the boiler, look in it at the back where you will find the circulating pump and flow and return, then follow the FLOW or RETURN. It's easy to identify the FLOW when heating is on if you are dealing with a mass of pipes in the hot press. All you can do it follow it around. A good way to find filling point if you are stuck is to have all the heating on and look for a cold 1/2" pipe coming off a hot pipe.

One good place to look if you are dealing with an old timer is in the attic as even though they may have removed the tank for the central heating they may have just linked the existing feed to the expansion pipe.

You may not find a filling loop, or a gauge or a return valve, you may just find a half inch tee going into the heating circuit

PS it is likely that you need to add inhibitor at a rad using the top end connectors and a funnel.

 

[RiverSide]

Thanks for the advice davidoco, your very right in that I was looking for things that just aint there. You know how you can get stuck in a problem and cant see the wood for the trees!

The old plumber tied the auto fill feed into the back boiler return system that I just blanked, so rather that the boiler just been like a rad on the system the damn back boiler line was also where the mian fill line inserted. there must be another connecting line some where else trickle feeding the system. I'm going to find it and remove the shagging thing.

I going back tomorrow to sort the damn thing out for once and for all.

I'm going to remove the auto fill line from the attic as the father in law really cant access it where it is.

He has a large boiler room onto the house and the main water runs through there with loads of free pipe space.

I'm going to fit a filling loop and add a pressure gauge locally as well.

I'll fit the filling point to the return line to the boiler and I'll stick a pressure gauge and pressure relief valve on thier own tee'd line on the flow out of the boiler.

I'll add fermox leak sealer and inhibitor while I'm at it, if the builders providers had a inhibtor charging connecting I'll stick that in the line as well to make it easier for the father to top up with out ruining the carpets by using the top valve.

It'll make life much easier for the father in law if everything is in place in the boiler house and he wont have to climb ladders.

 

[davidoco]

I'm going to remove the auto fill line from the attic as the father in law really cant access it where it is.

He has a large boiler room onto the house and the main water runs through there with loads of free pipe space.

I'm going to fit a filling loop and add a pressure gauge locally as well.

I'll fit the filling point to the return line to the boiler and I'll stick a pressure gauge and pressure relief valve on thier own tee'd line on the flow out of the boiler.

If removing pipe work for heating that is going to attic in say a hot press cap it at a height just above the highest rad in house with a 1/2" automatic bottle air vent.

Good idea out in the boiler room (I'd love one of those). Re fitting filling loop it is best practice to work on the return line where you would normally fit on a tee at lowest point the drain off, then the expansion vessel, then rising to filling loop, then rising to auto air vent.

 

[RiverSide]

Thats a good idea about the bottle vent if i cant remove the pipe itself I'll do just that.

This system had a back boiler on it so the circ pump is on the return line should i swap it onto the flow out of the boiler?

The current set up is like this:

The circ pump is on the return into the boiler.

The flow out of the boiler onto the main rad line under floor into first rads and on into the hot press on the ground floor and goes to the top of one side of the dual clyinder, this line is tee'd off and goes up into the expansion vessel in the attic over the 2nd story.

Should i move the expansion vessel out into the boiler room and place it on the return line as well?

I have a drawing posted on the ukplumbersforums titled very puzzling heating systems problem post 67851) as i said i'd ask else where as well.

Not your advice isnt really appreciated. Its great to bounce an idea of someone.

 

[davidoco]

This system had a back boiler on it so the circ pump is on the return line should i swap it onto the flow out of the boiler?

No pumps are not designed to operate at the high temps on the flow.

Should i move the expansion vessel out into the boiler room and place it on the return line as well?

Yes move it down out of the attic and arrange it so that water can always flow into it. I find that vessels get damaged if there is air trapped in them so position it so that it does not collect air by having it low down and pipe coming from the top.

That 3/4" unknown on the first drawing is/was probably the expansion pipe to the attic for the old back burner. Back burner should ALWAYS have an expansion pipe and be on an open system NEVER sealed.

 

[RiverSide]

Thanks davidoco, I'm only used to dealing with system on ships with much larger pipes, pumps etc. and I've never had to redesign a system, its one thing making a mess of your own place but your in-laws wouldnt be the best place to start bringing down ceilings.

On ships the higher grade pump often get inserted into a flow out.

I going to add a magnaclean filter on the new return line set up that I will install in the boiler room.

The returns from the rad and hot water circuit will join a longer line to the pump, I'll mount a filter on the line, the exe vessel on a tee, filling loop on another tee, and the pump into the boiler.

Out of the boiler the line splits to the hot water loop and the rad loop which has a zone valve fitted.

I'm goin to add a tee before the spilt and place a relief valve and pressure gauge onto it.

I'll have to run discharge lines c/w tundishes from the relief valves in the boiler room to round of the job.

As well as having to run a power cable for the boiler, you should see the pulg for the burner and power for the pump and thermostatic controls are hanging in midair infront of the boiler reaching across the boiler room to the wall socket. Its mental looking.

I'll leave the pipe to exe vessel in the attic in place but add an air vent there as that is the highest point on the rad loop. The hot water has an air vent added but I'm going to raise that of the ceiling on a wooden block maybe just so it can be found again in the loose blown insulation.

Then I'll do a system clean with fernox, do a number of flushes with clean water, test with a strip and if needed add a neutrilizer if needed.

I found the small weep when opening the floor so I guess there maybe more after the system is clean I'll add a leak stopper so it might help.

Would this be over kill or will it help at all.

 

[davidoco]

I going to add a magnaclean filter on the new return line set up that I will install in the boiler room.

Had to look that one up - if you get the system clean and add inhibitor there should be no reason for a magnaclean filter - I have never seen one installed - it won't do any harm.

I'll have to run discharge lines c/w tundishes from the relief valves in the boiler room to round of the job.

Tundishes etc most plumbers think hard of fitting a discharge to the relief valves let alone tundishes.

The hot water has an air vent added but I'm going to raise that of the ceiling on a wooden block maybe just so it can be found again in the loose blown insulation.

Don't have the bottle vent anything but vertical. If it is there years probably just as well to change it for the few euro they cost.

 

[RiverSide]

I'd still like to include a filter davidoco,

I've posted these pics on the other site, would you have any thoughts on the questions at the bottom.

"Figured out where all the pipes were going.

The mystery 3/4" line was tee'd into the auto fill and the expansion line as per the red line on the drawing below

"MYSTERY PICs"

I'm going to remove the auto filling system and refit everything in the boiler room like the drawing below

"New Parts"

The main return is about an inch of the ground and only has a foot of run to the pump and another foot to the bottom of the boiler.

I will if I can:

1. Stick in an extension of pipe running out in a loop and then into the boiler.
2. Tee'd of that line wil be my bits and bobs.
3. The Exe Vessel will be wall mounted about a two feet of the ground to give me lots of nice open space and easy installation. This is fine if I have the vessel mounted opening up and the pipe coming off and going down.
4. Should I attach the filling loop before or after the vessel?, I'm thinking before.
5. I will have to tee the magnaclean in upright so I'll have an interest arrangement of pipes, along the floor changing to upright, into magaclean, outta magnaclean, and back down to the floor into the resited pump.

I have a vertical return pipe from the hot water circuit dropping down the wall and teeing into the RAD line before the old pump, the magnaclean filter wouldnt work as well there I take it because the full flow of the system isnt passing through it all the time.

But would my completcated arrangement of pipes create to many bends before a pump and incress my chances of wear here?

 

[RiverSide]

Just a wrap up note to say thanks davidoco, job done and dusted.

found lots of intereting kinks in the system that are now gone and the heating is working a charm.

In the end i went for a very simple arrangement of pipes as possible I couldnt put the filter in the ideal place on the feed to the rads, but I put it in the second best as recommended by the maker just before the rads main line.

Airlocked the main cly coils which were a nightmare to get out but a slowly and steady cleared the air out.

the system works a treat now, charges really fast and is simply to operate with no climbing into the attic involved. The system pressure is holding steady at 1 bar while cold so I have no majorleaks anywhere but I'll keep and eye on it.
I have to clean and inhibit the system and I'm going to leakseal as well over the next few weeks.

just a note on the maganaclean professional filter I fitted, comes with ok instructions and all the bits you need and is supllied with chromed fittings to join your central heating pipes, BUT....the body of the filter is plastic and the threads are VERY EASY to crossthread, anyone fitting it should take great care to fit the shutoff valves to the body and then to the pipes, the filter costs at least 100 euro and the thread are plastic very poor design IMHO.

 

[RiverSide]

Oh Davidoco what would a plumber have charged me for all this work to be done not counting all the parts and pipe that I bought, just labour?