please help stove wont heat rads

stovenovice

i hope somebody can help. a friend of mine has a solid fuel stove (linked in with oil boiler) which manufacturer says will do 5-6 rads. yet when the pump is on at 50^c it only stays on for 10 mins. he uses the oil heating for an hour or so first so water is good and hot in system as it spills between oil and stove link-up on the returns.

the stove is supposed to give 8kw to rads and cylinder and his rads ( 6 ) total around 34000 btu and then cylinder on top. given that there may not be enough from stove would balancing of all the rads help?............or what else can be done?

pumps from both the stove and boiler are on the flows with non-return valves after pumps to stop heat from stove flowing straight out to boiler though it still spills between the returns..........help!!!!

SEVERA

is speed on pump too low
is gatevalve on solid fuel coil open too much
are they burning enough fuel to produce heat for rads
is it a good quality stove from reputable manafacturers

Billy Bunting

are they burning enough fuel to produce heat for rads

As Above, huge difference between coal and turf

stovenovice

burning coal and the stove is hopping.
the pump is on at 2 outa 3. its a dab v55-130. no gate valve on solid fuel coil in cylinder. moved stat to flow to see what that might do.

Sparkpea

surely all feeds from the stove should be unrestricted? i.e. no gatevalve on the coil at the cylinder from stove? I know its safe as houses so long as its open but some random will come along when theres a leak and turn off all valve in sight and someone may forget to turn it back on then boom.. mess

Billy Bunting

stovenovice wrote: »

moved stat to flow to see what that might do.

If your heating the water in the stove faster than that heat can flow (on gravity)to the cylinder then the pipe stat needs to be on the flow. If its on the flow it will kick in earlier.
Using a solid fuel stove linked to oil isn't as straight forward as you would think.

stovenovice

Billy Bunting wrote: »

Using a solid fuel stove linked to oil isn't as straight forward as you would think.

Never a truer word spoken! the idea originally had been to satisfy the cylinder before pumping to the rads hence the stat on the return.

there is a fairly substantial horizontal run when the flow goes into attic space before it drops into cylinder, is there a minimum this should be?

SEVERA

Sparkpea wrote: »

surely all feeds from the stove should be unrestricted? i.e. no gatevalve on the coil at the cylinder from stove? I know its safe as houses so long as its open but some random will come along when theres a leak and turn off all valve in sight and someone may forget to turn it back on then boom.. mess

from my experience with solid fuel,the rads will heat much better {get more circulation} if you have a gate valve on the coil return pipe, which is usually left between a quarter to half open depending on the size of the primary coil pipework but these should be 28mm. once a balance has been achieved between hot water and space heating take the knob off the balancing gate valve to stop it being tampered with, even in the event that someone does close it with a spanner, the flow pipe has an open vent to the expansion tank and the rads would take the extra heat being produced,and the occupier of the house would be aware that there was a problem as no hot water would be available to them.
they in turn would call a plumber who would rectify the problem. i would always put the pipe stat on the flow and set it to 40 degrees Celsius, also pump on return pipe as close as possible to stove on speed 2.
if this doesn't work check whether the vent in the attic is pitching hot water into the expansion tank, if it is extend the vent pipe as high as the ridge board of the roof before bending it down again over expansion tank{ no plastic piping to be used for this}

zxcvbnm12

sparkpea is 100 per cent right.it cud be lethal to put a gate vlv on the coil

SEVERA

zxcvbnm12 wrote: »

sparkpea is 100 per cent right.it cud be lethal to put a gate vlv on the coil

sorry but i have to disagree ,absolutley no problem having a gatevalve on the return on coil not even slightly dangerous if you think about it.
they say the proof of the pudding is in the eating and i must have fitted well over 100 solid fuel linked with oil boiler and gas systems in the last 20 years, i have allways found this to be best practice. its the same as balancing a rad circuit, if you have too much flow on one rad it starves the ones at the end of the circuit.
but allways have your non returns on the return pipes never the flows and never have any pump, non return vave or gatevave on a flow pipe from a solid fuel appliance the flow pipe should allways remain unrestricted.

zxcvbnm12

i just always thought u should have one un restricted circuit on solid fuel but u obviously have the experience.im just wonderin severa are u a plumber.i posted a thread "shower pump problem" last saturday.cud u give me ur opinion please

Sparkpea

I know a balancing valve on the coil always helps any system but in my opinion the correct way is to have it unrestricted then once the stat thats 2/3's of the way down the cylinder reaches 55/60 degress it brings the pump on to take the excess heat away from the coil and pump it to the radiators. The primary objective is still for hot water, then radiators - otherwise the boilers would be big enough to heat all rads not just 4, 5, 6.

I know what you're saying 100% about the balancing valve and set it then remove the head etc. even using the lock shield type valve would be safer but I'm just saying its something that I would never contemplate doing. I would never want that slight risk on my conscience incase anything did ever happen.

No matter what way we dress it up the fact is more and more people are doing DIY plumbing and touching things they think they know about or valves to try this and that - you just need to read this forum daily to see that 80% of people actually have no clue and many admit it - but it won't really stop them - the little advice they get on here they think they know what they are doing then but its far from the truth.

Billy Bunting

sorry but i have to disagree ,absolutley no problem having a gatevalve on the return on coil not even slightly dangerous

I'm not 100% on this one, i am sure you never put any restriction on the vent pipe and IMO i would never put any balancing valve/gate valve on a circuit that is relying on a gravity flow to operate, not because of any danger, the vent is there for that purpose, but restricting the circuit will simply stop it from working or at best slow down the gravity flow.

DoneDL

The primary pipework from the stove to the cylinder must be unrestricted, it is worth fitting an injector tee where the ch pipework meets the return to the stove.