heating system layout

[crzybkr73]

hello i am not a professional plumber but understand the system ok. but i am confused with the heating system. i am building my own house and doing as much as i can myself. boiler, rads, bathroom and kitchen no problem. but, i am installing a solid fuel stove, with boiler in the kitchen, and a back boiler in the sitting room which backs onto it. my hot tank will be situated above all this. can anyone help with sample layouts or advice on it. i'm confused as to how many pumps i need, is it a seperate one for each system.

 

[buffy27]

solid fuel.....are u definetly piping both,could u use 1 only.{u can use 2,try to decide wheather or not u will light both regularly ,alot of hassle each day }
there are alot of specifics i need to know to help u .
what other heating mediums have u {oil / gas}
are u going with open vented.
what type of domestic set up will u have.
copper cylinder?
how many coils.
will they b doing dhw and heating
there is so many ways to plump such a system.
go in to detail on intended set up .

 

[crzybkr73]

thank you for your quick response. to be honest i thought these forums were mostly a con. well i will be using both quite often as its a fairly large bungalow(75' x 32'). they will both have an open chimney. the stove is for daily use, and the fireplace in sittingroom is for evenings etc. i do also have an oil burner outside. i have a dual coil copper cylinder, and was going to pipe the oil into the top, where the electric element usually goes. i want to use a stats to control the system ,eg when fire is at optimum temp stat kicks in to circulate water around cylinder, thus heating water for taps, etc. also want to set a stat to make rads kick in at a certain temp also. do i need seperate pumps for the stove, fireplace, and central heating, or will one pump do both solid fuel systems, and a seperate pump for rads, with a motorised valve stat linked to them. the oil burner has its own pump

 

[buffy27]

what u want is a dual heating set up.indirect SINGLE coil copper cylinder.
one coil for oil and for b boiler.there will need to b t's then to rad circuit.this needs to b open vented , with f&e tank .the b boiler pipe work should be 1 " copper this will circulate itself by natural convectional heat currents. put the expansion pipe on the common flow from boilers{oil and bb} and top up on return.the flow from the boilers need to go to top of coil and return from bottom.u need a belly stat on cylinder which is wired to a motor ised valve and pump. this may be set at say 70c where when the cylinder is satisfied to this temp it will operate the motorised valve and a pump to pull from rad circuit.the flow from oil and flow from bb will join together before entering coil,u have a common over flow pipe and common top up.between where u join the two f's and r's and the coil u cut in the f&r to the rads .motorised valve on say flow and pump on return[pulling out of rads}
u will need to put a non return valve on both returns to oil and bb [prevent one heating the other}both can operate at the same time.
this is the most straight forward way of doing this system .there are many ways to do such a system.i have not done a system with two bb my self, because i would advise to use one or the other.they could use the same primary f & r with a third non return on the second backboiler{this would work in my mind]
u could also pump from the b b 's instead of using convct heat crts.
not to easy to explain this stuff .if i could sit u down with a pad , there would be no bother.
could u tie in with a plumber locally,have him take a look {pay him for his advice lol},
see , u want to do it right . hanging rads,putting in ware-fair play if u can do it , but piping a system correctly is a different kettle of fish.not doubting your ability-this is not a straight forward set up.the post is up with a nice few hrs, alot have viewed , but not too many answered... speaks for itself.its not straightforward.
i will help u with any questions u have[if i can] buf

valve on oil boiler return and on b boiler return.

 

[HTB]

crzybkr you need to well aware that the allowance for expansion on the system you describe is critical.

If you get your valving or controls wrong, or you include a device (eg zone valve or gate valve) on the expansion runs (but you shouldn't) then the potential for explosive failure is high. When I was doing my 6088 a few years ago we spent a great deal of time discussing the design of such systems and remember solid fuel systems are nowhere near as precise as gas, electric or oil.

I haven't been around for as long as many of the plumbers/gas fitters on here but even I am aware of spectacular stories of back boilers exploding because the clients returned from holiday and lit the fire without realsing that the F+R pipes where frozen,, with catastrophic results, and I am also aware of a situation where a gate valve was left closed after maintenance causing a similar result. The gate valve shouldn't have been there according to my instructors. Be very careful.

 

[justlead1]

Hi. In my opinion keep it easy. Although it seems pumps,stats and m/valves are used on multi fuel/appliance systems now days, i never feel comfortable with solid fuel boilers being reliant on pumps andmotorised valves. In the event of power failure and the appliance boiling, the energy developed and noise created can be quite dangerous and frightening. As is shoveling hot coals from the fire and scalding hot water being discharged from taps to reduce the heat.
If as you suggest both solid fuel stoves are at the same level, with the cylinder a floor above, why not use gravity circulation with 28 mm or 32 mm F & R along with cold feed and vent ? If connected together at cylinder level prior to entering coil of cylinder, one boiler will not heat the other,. This will allow the oil system to be conventional, cylinder stat, room stat, timer etc. Good Luck

 

[buffy27]

crzybkr you need to well aware that the allowance for expansion on the system you describe is critical.

If you get your valving or controls wrong, or you include a device (eg zone valve or gate valve) on the expansion runs (but you shouldn't) then the potential for explosive failure is high. When I was doing my 6088 a few years ago we spent a great deal of time discussing the design of such systems and remember solid fuel systems are nowhere near as precise as gas, electric or oil.

I haven't been around for as long as many of the plumbers/gas fitters on here but even I am aware of spectacular stories of back boilers exploding because the clients returned from holiday and lit the fire without realsing that the F+R pipes where frozen,, with catastrophic results, and I am also aware of a situation where a gate valve was left closed after maintenance causing a similar result. The gate valve shouldn't have been there according to my instructors. Be very careful.

i always install a 3 bar blow off piped to outside when doing b boilers,as an added safety device.i would do this always if adding pipe stats with pumps for circulating/motorised valves}back boilers have recieved bad press - but the bad press should only be on the twits installing them.

 

[HTB]

That sounds like excellent advice. Where excactly do you install the blow off? I would assume that the pipe sizing etc for the blow off would follow similar basic principles to unvented cylinders and combi's.

 

[buffy27]

That sounds like excellent advice. Where excactly do you install the blow off? I would assume that the pipe sizing etc for the blow off would follow similar basic principles to unvented cylinders and combi's.

when i am rumming pipes in dead work[first fix]i run qual pex to within about 2/3 mtrs from boiler, a 310 joiner and copper to come up next to f&r at boiler.3/4" piping

 

[crzybkr73]

i thank you all for your quick and informative responses to my little problem. i am not too well aquainted with all the terms in use as i gained my experience from an old school guy who had his own names for everything in the world. i guess i may need to get in a professional for some on site advice at some stage for sure.to clear up a few points then, i do not need a seperate pump for each boiler. i can connect the fireplace or stove to the oil, but not to each other.
so far i have 1" coppercoming out of both solid fuel systems to copper tank, with seperate 3/4" copper to overflow(expansion) tank above the cylinder, with non-return valve on both, with each going to seperate cylinder coils(one to each side). also i have 3/4 pex going to top each system up again, also with non-return, just incase. each has their own pump and pipe stat. the oil is seperate too, going to top of cylinder. all three are then tee'd into the rads, which has its own pump and motorised valve. what i am worried about is will each interfere with the other if two or more are operating at once. perhaps some of your suggestions would be better, as in combine the two solid fuel systems and use convection to circulate. they shoul circulate anyway i think, but i put in the pumps for extra safety, but in the case of power failure they might cause a backup in pressure, but i'm not sure.
also after the rads pump i split the rad supply line into two seperate systems(front and back of house)because of the length(75!)of the house to try to equalise the heat, but they join again before reentering the system. wasw this a good idea or just a waste of materials

once again thanks to HTB, justlead1, AND buffy27, FOR YOUR VERY HELPFUL AND FRIENDLY ADVICE

 

[HTB]

Crzy I assisted in installing a wet Solar panel system once and the company had patented a device they called a "collector box". It was quite simple but I had to sign documents guaranteeing contractual confidentiality (it was being patented at the time) so I darent say too much about it, but in essence you could feed as many heat sources into it as you wanted and because of the internal shape it only took heat from a hot source leaving the others. It required Zone valves and thermisters for best efficiency, but it worked quite well. I'll see if I can dig out stuff on the company and post it on here.

 

[stevetheplumber]

not sure what the temperture limits are on pex pipe but id be very wary of using it anywhere with a back boiler which can produce very high temeratures even under normal use
i would definatly keep it as simple as possible gravity primaries and pump the heating
would having two fires going produce to much heat?causing scalding water ?possibly to the point of boiling ?

 

[crzybkr73]

thank you steve also. i think i will be going the gravity/ convection road for sure. it is a lot simpler that way. would it be ok to install a pump on the return for extra boost to the boilers in case the fires get too hot or will convection be sufficient

 

[buffy27]

not sure what the temperture limits are on pex pipe but id be very wary of using it anywhere with a back boiler which can produce very high temeratures even under normal use
i would definatly keep it as simple as possible gravity primaries and pump the heating
would having two fires going produce to much heat?causing scalding water ?possibly to the point of boiling ?

yes i agree with u totally.blow offs when activated do exactly that ,they blow off.normally one blast of a few secs.
ideally there would be a spider after setting up residence in the blow off.[if things piped an d controlled right]
1 " qual pex at 3 bar can cope with 9 3 degree hot water and i think copes with around 12o degree for short bursts.
the way i was talking about running it was with a few meters of copper first ,connected to the qual pex.[this is only a blow off,not in constant use ,well for the spiders sake anyway.] have i defended myself?