Dual central heating query

billy_beckham

Hi all,
could someone please put up a diagram of how to connect up an oil boiler and solid fuel stove through a dual coiled cylinder, and have either or both supplying radiators?

Failing that even an explaination of how to do it?

Would be much appreciated

kay 9

Not being smart, but are you a plumber? Stay away from connecting solid fuel if not. It's highly dangerous. It's not easy put up diagrams as every system varies greatly.

Buford T Justice

This is not a DIY job. You need a plumber

billy_beckham

kay 9 wrote: »

Not being smart, but are you a plumber? Stay away from connecting solid fuel if not. It's highly dangerous. It's not easy put up diagrams as every system varies greatly.

I am not a plumber, I do not want to do this myself. I merely wanted to understand/see how it would be done on a basic setup. Diagrams, advise etc are put up on other forums without any fuss. eg electrical

Fingers McGee wrote: »

This is not a DIY job. You need a plumber

Again not looking at this from a DIY point of view.

Buford T Justice

The guys on electrical can sometimes be reluctant to post advise on things to non-electricians.

Anyhoo, I've no diagrams, but basically you have one circuit going from F&E Tank, to boiler to cylnder to rads.

Back boiler goes from F&E Tank to back boiler to cylnder on separate coil to existing heating system by the use of non return valves, to prevent the heat from the back boiler to the boiler.

Feel free to correct me if I'm wrong here.

billy_beckham

I've attached a very rough sketch:D of how I think a dual system would be hooked up, but I am unsure of where the non return valves that fingers talks about would go, perhaps an "expert" might advise. I'll sign a disclaimer if necessary...:)

realmadrid

use a systemlink its on the web somewhere

Buford T Justice

You need to re-do that diagram. Where the pipes you have drawn cross, you need to show which ones join the cross, and which ones jump over it.

You need NRV's where the pipes from the back boiler join into the OFCH system, to prevent the boiler heating the water in the back boiler, and you need NRV's on the OFCH side at roughly the same point to prevent the back boiler heating the water in the oil boiler.

Also, you should not be doing this with a closed system, back boilers should be on an open system only

billy_beckham

Ok, re-did drawing. Put in 4 NRV's and showed a F+E tank. Hopefully its clearer. Don't know if the oil side needs a cold feed too??

Buford T Justice

Yes, cold feed needed to both sides from the F&E Tank. Its a difficult diagram to follow, as height is also an issue for rads in comparison to F&E etc....

Just to note, you should be feeding the rads after the Cylnder.

You really need a plumber OP.

billy_beckham

Ok so cold feed needed to both sides, what about the position of the NRV's? Its a bungalow so F+E is above rads. Basically its a feed off each flow and return to the rads flow and return............And its a plumbers mess I'm trying to sort out!! :mad:

Buford T Justice

Why don't you tell us the problem, and maybe we can help.

kay 9

If it's a job that is already botched, I'm sure we can help or put you on the right track. What's wrong with the system at present?

billy_beckham

I've attached a drawing of the system as it's currently installed, as far as I can see. The issues are, the expansion on the stove side sends water to the tank (i think when both pumps are running) and it over flows. There has been some terrible bangs from the hotpress (have turned off oil boiler because of this) also automatic vent on boiler was blowing steam this evening.

I think the two systems are not isolated from each other properly and that the oil side runs low on water when the stove pumps kicks in... have also had to bleed rads several times........

Joey the lips

realmadrid wrote: »

use a systemlink its on the web somewhere

System lex i think its called...but i get the picture...its brilliant and invented by an irish man

kay 9

It's hard to imagine the entire system from the drawing and one would need to seee it in reality, from what I see you should have an Nrv at the boiler.

Buford T Justice

billy_beckham wrote: »

I've attached a drawing of the system as it's currently installed, as far as I can see. The issues are, the expansion on the stove side sends water to the tank (i think when both pumps are running) and it over flows. There has been some terrible bangs from the hotpress (have turned off oil boiler because of this) also automatic vent on boiler was blowing steam this evening.

I think the two systems are not isolated from each other properly and that the oil side runs low on water when the stove pumps kicks in... have also had to bleed rads several times........

Ok.
Firstly, is the water pitching when the stove is in full swing? and is the pump running when this is happening? Where is the stat that controls the pump located?
I'm trying to establish if the water is boiling over in the stove before the pump kicks in or not.

Are you sure that you are talking about the auto air vent on the boiler and not the pressure relief valve? (PRV has a red knob on the top of it)

At any rate, you need to stop the heated water from the stove flowing through the oil boiler and vice versa. My suggestion is to put a non return valve on the feed of both supplys, which will prevent water back flowing through the other system.

Other than that, it can be quite difficult to diagnose without actually looking at it.

Is it possible that the two pumps, when on are actually pumping against each other currently?

billy_beckham

Reply

Fingers McGee wrote: »

Ok.
Firstly, is the water pitching when the stove is in full swing? and is the pump running when this is happening? Where is the stat that controls the pump located? Issue seems to occur when both pumps are running, stat for stove pump is on flow of stove just before cylinder.I'm trying to establish if the water is boiling over in the stove before the pump kicks in or not.

Are you sure that you are talking about the auto air vent on the boiler and not the pressure relief valve? (PRV has a red knob on the top of it). Positive
At any rate, you need to stop the heated water from the stove flowing through the oil boiler and vice versa. My suggestion is to put a non return valve on the feed of both supplys, which will prevent water back flowing through the other system. I think myself that when the stove pump kicks in it is pulling water from the return of the oil boiler as it is physically closer( in hotpress) and on the return of the rad circuit. This I think is what is causing the overflow and possibly starving the oil boiler of water. In terms of fixing the issue I have some ideas and am looking to know what ye guys think before getting the guy back.

1. Cold feed to oil boiler side
2. NRV on flow and return of oil boiler

I have attached what I think system should be like and would love some feedback, my parents are freezing:(Other than that, it can be quite difficult to diagnose without actually looking at it.



Is it possible that the two pumps, when on are actually pumping against each other currently?

Buford T Justice

One non return valve will suffice for the OFCH, and one for the Stove. As its a complete circuit, if you stop the backflow in one place, it stops it for the whole circuit.

Add a cold supply from the F&E Tank as you also suggest, and see how that goes.

Meantime, I would suggest using one or the other system at any given time.

Also, are both pumps working correctly?

billy_beckham

Both pumps are coming on when they are supposed to, I'm gonna get him back next week to do the modifications...

Deesse

I have a GFCH system and would like to add an old Rayburn range. I am wondering if i could simply slot the range into the return pipe to the gas boiler? It would be heating the return water and when the range is lit it would be supplying the return pipe with water sufficiently hot enough to switch off the gas boiler thermostat (on the flow pipe i think). I could wire the remote gas boiler pump in parallel with another thermostatically controlled circuit to come on when the range is hot. OK one or the other would be acting as radiators when the other was operating, but they are both in rooms that i want to heat anyway. I could put a pressure release valve near the range piped to the outside. I am a physicist and this seems logical to me, but i may be missing something obvious to someone with more experience in this area?

Paddy Pieball

Ive just signed up on this boards thing and one thing Ive learned very quickly ,most posts are written by DIY people who havent a clue .
This is more of a warning than anything else.
WHEN FITTING ANY SOLID FUEL APPLIANCE WITH A BOILER YOU MUST HAVE AN OPEN CIRCUIT TO CYLINDER USING TWO PIPES .
THE WATER MUST HEAT WITHOUT PUMP AND HAVE AN OPEN VENT TO TANK OFF TOP OF FLOW PIPE DO NOT UNDER ANY CIRCUMSANTNCES WHATSOEVER FIT NON RETURN VALVES ON SOLID FUEL TO WATER ,NO MATTER WHAT SCENARIO IS INVOLVED.
I DONT CARE WHAT YOU DO AFTER THAT

shane0007

Paddy Pieball wrote: »

Ive just signed up on this boards thing and one thing Ive learned very quickly ,most posts are written by DIY people who havent a clue .
This is more of a warning than anything else.
WHEN FITTING ANY SOLID FUEL APPLIANCE WITH A BOILER YOU MUST HAVE AN OPEN CIRCUIT TO CYLINDER USING TWO PIPES .
THE WATER MUST HEAT WITHOUT PUMP AND HAVE AN OPEN VENT TO TANK OFF TOP OF FLOW PIPE DO NOT UNDER ANY CIRCUMSANTNCES WHATSOEVER FIT NON RETURN VALVES ON SOLID FUEL TO WATER ,NO MATTER WHAT SCENARIO IS INVOLVED.
I DONT CARE WHAT YOU DO AFTER THAT

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