Adding back boiler CH to Oil Burner CH

LazyPaddy · 03-01-2010 12:46pm #1

Hi Guys
I am an enthusiastic DIY'er and have had a good bit if experience with BASIC plumbing. I want to add a Solid Fuel Back Boiletr CH system to my exisating Oil Burner CH. I have a dual coil cylinder as I anticipated this when building. The Oil Burner is connected to one coil of the burner and also to the radiators. At the minute the Solid Fuel pipes are ONLY connected the the other coil. I would like to add the Solid Fuel to the radiators as well but realise that I will be linking 2 systems. I have heard that I must add non-return valves but no-one can tell me where or why.... Do I need to add anyything else??? A simple line diagram would be really cool. The oil burner circuit is an open vent circuit. The pump for the burner is out at the burner(external burner). The pump for the Solid Fuel is in the hot press and I have ran a cable from the Solid Fuel stove to the hot press for a pipe stat to control the pump. Any advise would be really great.

volvo 240 · 03-01-2010 2:02pm

Hi,

You have three ways to do the job safely!!

1 A dunsley neutraliser that you install under the hot water cylinder or other models shown in the link. http://www.dunsleyheat.co.uk/linkupsys.htm Probably the most cost effective option.

2 A H1 control panel http://www.h2panel.co.uk/h2index.htm

3 A thermal store with 2 sets of inlets/returns for the boilers. Something like this this set up. http://www.yeoman-stoves.co.uk/pdf/yeoman-linkup.pdf Don't forget the heat leak rad or rads!! James.

items · 03-01-2010 4:05pm

Most tend to go back boiler for cylinder, oil only for rads. When you combine both your running into risks, joining a sealed system to a vented. You can do it but the effort required doesn't bring benefit.

Back boiler will only heat cylinder and a few rads, even then cylinder is loosing out as heat is also going to rads. To make most out of back boiler, most stick to only cylinder in this case. With only cylinder you getting most out of back boiler if you get me.

When combining both you have to install NRV's as you've mentioned, also separate circulation pumps along with heating control of both. To be honest, I would'nt recommend a DIY'er combining sealed along with vented.

demanufactured · 03-01-2010 4:37pm

Items you didnt read his post, He said the oild burner is on an OPEN circut.

LazyPaddy · 03-01-2010 6:02pm

Thanks a mil Volvo 240. They seem to be exactly what I need. I was assuming I might need to build these from scratch, but looks like I don't have to. Of them all, which would you reccomend and why??? I am leaning towards the H2 panel. Simply seems to be better laid out. I am a controls engineer so I would look forward to getting stuck into the electrical end of things. The plumbing would be a good challenge

Thanks again

Micky Dolenz · 03-01-2010 7:07pm

Control panels aren't needed.

You must fit NRV's, This prevents the stove from heating the oil boiler when it's on and visa versa, a huge waste of energy.

You need to have two one inch pipes from stove to cylinder. Natural circulation is a must with solid fuel. the only wiring you will have to do is between pipe stat and circulation pump.

Describe you hot press.Do heating pipes from boiler travel directly to cylinder and then rad circuits are tee'd off in hotpress? Have you zoned heating? This will need to be bypassed by the stove circuit as it will always require an open zone to pump too.

A bit tricky for a DIY'er I would say, but not impossible.

LazyPaddy · 03-01-2010 7:28pm

The circuits at the minute are as follows. Solid fuel 1" pipes from solid fuel stove(downstairs) to hotpress (upstairs). The flow pipe goes from the solid fuel up the wall into the attic and the drops down to the hotpress. The return runs along the downstairs floor and rises up to the hotpress in a flase partition wall. This is ony connected to the coil of the cylinder. The pump is in the hotpress and a cable is ran from the stove to the hotpress for the pipe stat to control the pump.
The oil burner circuit runs from the burner outside to the hotpress upstairs. It is teed off to the other cylinder coil and the radiatirs via motorised valves. As I said already it is an open circuit as is the solid fuel. If I was to connect the flow of the stove with the flow of the oil burner and same with the returns, I would indeed heat up each others boiler when not in use. Where do I place the NRV's and what else should I do???

Micky Dolenz · 03-01-2010 7:42pm

You have natural circulation which is great..

where are the motorised valves for heating zones?

You would normally tee from the flow and return off stove into rads in the hotpress. once you have tee'd of 1inch pipes you would fit your pump and NRV, the other NRV would be fitted at the pump on the oil circuit.

volvo 240 · 03-01-2010 8:25pm

Micky Dolenz wrote: »

You have natural circulation which is great..

where are the motorised valves for heating zones?

You would normally tee from the flow and return off stove into rads in the hotpress. once you have tee'd of 1inch pipes you would fit your pump and NRV, the other NRV would be fitted at the pump on the oil circuit.

Not how I would recomend doing it at all!! If the NRV are installed in the wrong location it could lead to the boiler exploding. Also make sure you fit the NRV in the correct direction!! Make sure you have seperate cold feed and vent pipes that are for each boiler and a gravity heat leak radiator on the solid fuel boiler and a safety valve fitted near the flow on the solid fuel boiler. Make sure that the cold feed and vent pipe have unrestricted passage from the boiler to the feed and expansion tank and that the non return valve does not block the feed and vent pipes should the NRV fail. closed etc. Otherwise big boom!! If someone proposed to do this in the UK I would run!! There is no way that this setup would get approval! The H2 panel looks good but I have never linked two boilers together so couldn't say which to go for. I would think the H2 costs more but it does look more sophisticated. Please get some trained heating engineers in and get them to quote you and ask their opinion on the non return valve idea. James:)

Micky Dolenz · 03-01-2010 8:29pm

volvo 240 wrote: »

Not how I would recomend doing it at all!! If the NRV are installed in the wrong location it could lead to the boiler exploding. Also make sure you fit the NRV in the correct direction!! Make sure you have seperate cold feed and vent pipes that are for each boiler and a gravity heat leak radiator on the solid fuel boiler. Make sure that the cold feed and vent pipe have unrestricted passage from the boiler to the feed and expansion tank and that the non return valve does not block the feed and vent pipes should the NRV fail. closed etc. Otherwise big boom!! If someone proposed to do this in the UK I would run!! There is no way that this setup would get approval! The H2 panel looks good but I have never linked two boilers together so couldn't say which to go for. I would think the H2 costs more but it does look more sophisticated. James:)

Approval from who? Please state BS on this.

How do you think it was done before the "H2" or other such non needed product was introduced?do you think this is a new concept in heating technology?

volvo 240 · 03-01-2010 9:01pm

Micky Dolenz wrote: »

Approval from who? Please state BS on this.

How do you think it was done before the "H2" or other such non needed product was introduced?do you think this is a new concept in heating technology?

Building regulations and Hetas requirements.
A quide on the linking up of systems.
http://www.solidfuel.co.uk/pdfs/link_up.pdf
If you want to offer advice that could be dangerous for a novice installer is up to you. We all have different views but I would only offer advice that is safe and to current working practice. How would you feel if "Lazy Paddy" came back to this forum to say one of his children/wife etc had been killed in a boiler explosion because of advice from this forum. If they did do it in the old days fine but technology has moved on to make thing safer. James.

Micky Dolenz · 03-01-2010 9:16pm

volvo 240 wrote: »

Building regulations and Hetas requirements.
A quide on the linking up of systems.
http://www.solidfuel.co.uk/pdfs/link_up.pdf
If you want to offer advice that could be dangerous for a novice installer is up to you. We all have different views but I would only offer advice that is safe and to current working practice. How would you feel if "Lazy Paddy" came back to this forum to say one of his children/wife etc had been killed in a boiler explosion because of advice from this forum. If they did do it in the old days fine but technology has moved on to make thing safer. James.

James, that is just sales literature from the company that sell that product. Where is the BS to back up your original claim?

Do you think that solild fuel stoves and gas/oil boilers haven't been connected for the last 25 years?

I'll explain in a more simple way.

Solid fuel must have a 1" natural circulation ciruit between stove and cylinder. On the return as close as is practical to the stove, shall be the cold feed. On the flow as close as is practical to the stove should be the expansion pipe. A PRV shall also be fitted on the flow pipe between expansion tee and stove.

This primary loop should have no valves (Inc pump) Off that primary loop is a secondary loop, only on this circuit should the pump and NRV be fitted.

How can what I suggest be dangerous? Do you think how this was done in the past and now is dangerous?

volvo 240 · 03-01-2010 9:57pm

Micky Dolenz wrote: »

James, that is just sales literature from the company that sell that product. Where is the BS to back up your original claim?

Do you think that solild fuel stoves and gas/oil boilers haven't been connected for the last 25 years?

I'll explain in a more simple way.

Solid fuel must have a 1" natural circulation ciruit between stove and cylinder. On the return as close as is practical to the stove, shall be the cold feed. On the flow as close as is practical to the stove should be the expansion pipe. A PRV shall also be fitted on the flow pipe between expansion tee and stove.

This primary loop should have no valves (Inc pump) Off that primary loop is a secondary loop, only on this circuit should the pump and NRV be fitted.

How can what I suggest be dangerous? Do you think how this was done in the past and now is dangerous?

I cant picture what you are trying to describe.
Here is a link up using non return valves. The return valves would block the flow if they failed and there would be no heat dissipation as there is no heat leak radiator in the drawing for the both boilers to heat the hot water cylinder. It would mean an awful lot of re piping too. In my opinion it would be easier to fit and buy the dunsley neutraliser for 300 pounds plus pipework etc. I will not be replying to this thread. If anyone is thinking of linking 2 boilers together please get professional advice James.

http://www.arca53.dsl.pipex.com/index_files/link.htm

items · 03-01-2010 9:57pm

demanufactured wrote: »

Items you didnt read his post, He said the oild burner is on an OPEN circut.

I did READ it cheers. From my take on post, heating system is being modified improved etc, sealing up oil side is the only way to bring improvement to that part of system. I've taken it that poster is sealing oil so gave advice with that in mind.

Micky Dolenz · 04-01-2010 4:27pm

volvo 240 wrote: »

I cant picture what you are trying to describe.
Here is a link up using non return valves. The return valves would block the flow if they failed and there would be no heat dissipation as there is no heat leak radiator in the drawing for the both boilers to heat the hot water cylinder. It would mean an awful lot of re piping too. In my opinion it would be easier to fit and buy the dunsley neutraliser for 300 pounds plus pipework etc. I will not be replying to this thread. If anyone is thinking of linking 2 boilers together please get professional advice James.

http://www.arca53.dsl.pipex.com/index_files/link.htm

What I am describing is how 90% of dual systems are piped here. The NRV sticking is a moot point, there is stll an open circuit to the cylinder. Things will fail esp pipe stats and pumps, power failures need to be considered too.

I don't disagree with your method, but how you can describe a tried and tested method over a few decades as dangerous, surprises me.

OP, as you can see, this is not your standard run of the mill plumbing job, My advice, get some pro's in to qoute it. Listen to what each of them say and make up your own mind.

LazyPaddy · 05-01-2010 11:09am

Hi Guys
Didn't mean to cause this fuss....Sorry. Anyway, I wnet to a buddy's house who has a similar setup to me and it is done with NRV's. The only thing he said was that he has a few problems (He did this himself and is not a plumber btw).
1)When he turns on his oil burner the pipes at the back of his solid fuel burner get warm, which he said is down to heat transfer as opposed to flow????
2)If he has his oil on for say 2 hours and the hot water gets up to a good temp, when he lights his solid fuel, the water hot water seems to cool down and then get warm again. I am assumin that the "cold" water flow from the stove is taking some of the heat out of the cylinder through heat transfer as well.
I am still a bit baffled about the positioning of the NRV's. Could someone please elaborate as to where they should be in each circuit and the purpose so I can relate i to my situation. I know that they are to stop the flow of each circuit reaching each others.
Also, after your comments am I right in assuming that, on the solid fuel circuits, the cylinder should be heated with convection and the rads with a circ pump. i.e. i should not have the circ pump pumping throught the cylinder. Also, you mentiuoned that I have "natural" convection. Could someone give me the idiots guide to convection. Thanks a mil guys and I am still debating the inter-link options. I cannot afford to get a plumber in at the minute to be honest hence the DIY job.

Deesse · 07-12-2011 3:11am

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?

heinbloed · 07-12-2011 10:33am

@ Deesse:
Perfect, logic. This is how central heating systems work when using two thermal sources.

Since your pump is decentral situated think about an intelligent pump,different thermal sources have a different thermal output. An intelligent pump (temperature controlled like for example the Grundfoss Magna serie, A rated) would help to distribute the thermal energy in an optimised way.

A bog standard pump would distribute as well, but solid fuel back boiler outputs differ due to changing fuel quality/efficiency and -input. Here the intelligent pump could optimise the system further.

Good luck!

07-12-2011 1:47pm

As a RGI and UK gassafe regerstered gas engineer I would advise that you can't put a back boiler, range etc.. on the same circuit as a gas boiler, it would be outside of manfactures design/fitting requirements as no gas boiler has been tested by a manufacture to work in this manor, the heat generated by the Range can have a negative impact on the gas boiler and this type of installation is outside of Irish Gas regs.

Adding back boiler CH to Oil Burner CH

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