Solid Fuel Fire with Primatic Cylinder

[wfoot]

Hi all,

Have a Solid Fuel Fire which heats hot water and heating.

Primatic Cylinder started leaking, so have replaced it with new cylinder, f. & e. tank and cold water storage tank.

Temperature of old cylinder was unregulated, so hoping to fit thermostat to side of cylinder which would shut off a 2 way valve. Central Heating side is pumped, but hot water side was gravity (i think?).

Basically how's the best way to go about doing this? Do I need a radiator connected to hot water side to dump access heat when valve closed?

Cheers

 

[sambotc]

Hi,

Yep basically you need a heat leak radiator as you have said. Presuming none of the other radiators get hot when the cylinder is being heated without the heating already.
Most common place to install this is in the bathroom to be used as a towel warmer although providing the radiator is installed to work on gravity circulation it's entirely up t you where you put it!

Sam

 

[holty]

forget the 2 port. its solid fuel, you have no way in regulating the temp of solid fuel.

 

[sambotc]

Sorry that is incorrect. Part L applies to solid fuel systems as much as it does to any other heat source so technically you have too.

Sam

 

[Paul Barker]

Well if you do install a valve between the solid fuel boiler and the cylinder wear waders when in the same room awaiting the inevitable explosion of boiling water across the room.

on the bright side it should be self mitigating as the water will put the fire out.

i suppose the energy efficient thing is to operate a solenoid valve as found on washing machines to put fire out when cylinder satisfied for heat.

 

[wfoot]

Surely any expanding water will expand into the f&e tank if it did over heat?

I am assuming that both heating and dhw are linked as they filled from single cold tank in old primatic cylinder.

Does that mean there is absolutely no way of regulating temperature in cylinder heated by solid fuel?

 

[sambotc]

As a precaution you can add a pipe stat to the return pipe which in the event of over heat, switches the pump on to run the heating circuit. Providing you have a large enough heat leak radiator which has been piped up correctly there should be no reason for the pump to run regularly.

Doing what has been described above IS the way to regulate heat to the cylinder and also of course save fuel and reduce carbon emissions

You could also add a thermostatic mixing valve to the hot water outlet and increase the cylinder stat to 80oC to minimise wasted heat lost via a heat leak radiator.

These are all standards as per HETAS manual.

Sam

 

[manortim]

well i'm in the middle of a install that uses a soild fuel boiler has its only source of heat.

its coupled to a underfloor heating pipe work.

28mm pipe from burner up to flow into cylinder, off that pipe is a pipe that goes to 2 heat leak radiators, on the return out of the cylinder is the 2 port valve, when the cylinder is satified, it closes and more of the heat goes to the heat leak rads. i won't go into further details coz its boring, but the system has 7 safety devices to make sure there is no chance of over heat in the system.

 

[Terrywookfit]

well i'm in the middle of a install that uses a soild fuel boiler has its only source of heat.

its coupled to a underfloor heating pipe work.

28mm pipe from burner up to flow into cylinder, off that pipe is a pipe that goes to 2 heat leak radiators, on the return out of the cylinder is the 2 port valve, when the cylinder is satified, it closes and more of the heat goes to the heat leak rads. i won't go into further details coz its boring, but the system has 7 safety devices to make sure there is no chance of over heat in the system.

Do these safety measures include preventing some stupid tw@t leaving the ashpit or loading door open?

 

[wfoot]

Just to get this straight.....

.......there is an open soild fuel fire with back boiler plus gravity fed dhw and manually pumped central heating.

If I was to fit a cylinder thermostat, with 2 port valve, could i then fit a pipe stat connected to the heating pump in order to dissipate the excess heat? As i say, presumably if the stat or pump failed it would lead to expansion up to the f&e and not a massive explosion?

Oh I didn't mention that the system is in a bungalow, where a gravity fed heat leak rad would have to go in the loft!!!!!

Don't know if any of you will find this webpage useful, but it has some useful schematics for Solid Fuel systems

http://www.arca53.dsl.pipex.com/index_files/cont3.htm

 

[sambotc]

Hi,

Yes you could. Make sure the 2 port valve is a 'normally open' type. This ensure's that in the event of a power cut the valve would still be open allowing the heat to travel around the coil via gravity.

Perhaps fitting a TMV and increasing the cylinder temp to 80oc would be more benefical. Having your heating sytem come on and off through the summer may not be very practical.
You can still run a radiator at ground level via gravity. All you would need to do is take the flow into the loft and down to the top of a radiator, then take the return back at low level to the return pipework. This radiator must NOT have a TRV or wheel head on, it must be 2x lockshields to prevent it from being turned off.

As i say these are all recommendations from the current HETAS manual which i have to hand so if you have anymore questions then fire away.

HTH Sam

 

[wfoot]

Am I being stupid, but not sure how you can get gravity flow up and down via loft?

Should have mentioned that cylinder is in loft too!!!! If valve closes off in loft, surely heat will build up there instead of travelling down to heat laek rad?

Would it be better to put rad in loft? Or is that a silly idea?

 

[sambotc]

Untitled

• sambotc
• 8 Aug 2008
• 4

sorry for the picture its about the best i can do!

You could put it in the loft but it would just be a waste of heat!

Sam
[/img]

 

[wfoot]

Many thanks for that Sambotc. Just need to figure out which is flow and which is return now!!!!!

Having difficulty finding a normally open valve, can you recommend anywhere?

 

[sambotc]

Hi,

Honeywell do a 28mm normally open valve. The valve is a V4043B1265. If you google that you will find some. Remember not to valve the cold feed or vent pipe off when fitting the valve!

Finding the flow is easy, just fire the boiler up and feel for which pipe gets hot first.

HTH Sam