Stove boiler over heating. Solution ?

chuck eastwood

Hey folks. You might be able to offer me solution to my stove overheating. So I fitted a system link right after they came out and a mate who is no longer a plumber ( the world is a safer place now ) helped me fit it.

My main problem is that when the stove circulating pump kicks it it only circulated to systemlink and back plus a gravity feed to the HW cylinder throttled on the return with an injector TEE.
 Unless I call for water to the up/downstairs rads the via 3 channel horstman I am left with the stove circulating through the systemlink and 1 coil, a fairly small volume of water which  i don't feel to confident leaving the house with the stove lighting as it starts banging after about 40 mins with a half decent fire even closed off.
It's a vented gravity fed set up
Should i stick a second rad in the room right above the stove as an extra buffer or like the drawing attached should I connect into the upstairs loop straight from the stove flow, I can throttle it so it isn't getting full flow direct from the stove while leaving the systemlink as priority. Open to suggestions. I can do the work myself as I work in hydraulics but I prefer to ask the pros for advice on the best solution.
The first drawing is the current set up, second is my proposed change (top centre of drawing)

chuck eastwood

Anyone

whizbang

Whats wrong with having the Upstairs rads pump running..?

Could you swap the injector ports to have the main flow to the HW cylinder?

chuck eastwood

whizbang wrote: »

Whats wrong with having the Upstairs rads pump running..?

Could you swap the injector ports to have the main flow to the HW cylinder?

It's not that I have a problem with it running but if out off the house and the stove is lighting the upstairs pump will not come on unless i call for heat from my 3 channel timer. I want the flow to be directed or used as soon as the stove circulating pump kicks in.

Changing the direction of the injector TEE defeats the purpose of having it fitted if it is then giving priority to the coil and not the system link. Also it wouldn't really solve the problem as the small volume of water is already enough to have the HW hopping. I need to move a greater volume of the heated water into the CH via the circulating pump.
Can you see any issue with my proposed change On the sketch ?
Thanks for your reply

John.G

chuck eastwood wrote: »

Hey folks. You might be able to offer me solution to my stove overheating. So I fitted a system link right after they came out and a mate who is no longer a plumber ( the world is a safer place now ) helped me fit it.

My main problem is that when the stove circulating pump kicks it it only circulated to systemlink and back plus a gravity feed to the HW cylinder throttled on the return with an injector TEE.
 Unless I call for water to the up/downstairs rads the via 3 channel horstman I am left with the stove circulating through the systemlink and 1 coil, a fairly small volume of water which  i don't feel to confident leaving the house with the stove lighting as it starts banging after about 40 mins with a half decent fire even closed off.
It's a vented gravity fed set up
Should i stick a second rad in the room right above the stove as an extra buffer or like the drawing attached should I connect into the upstairs loop straight from the stove flow, I can throttle it so it isn't getting full flow direct from the stove while leaving the systemlink as priority. Open to suggestions. I can do the work myself as I work in hydraulics but I prefer to ask the pros for advice on the best solution.
The first drawing is the current set up, second is my proposed change (top centre of drawing)

The proposed modification looks promising as it gives a additional heat loading other than from the cylinder coil, I suppose one might say that the zone pumps should/could have wired in parallel with the stove stat originally?. and would start irrespective of what the programmer is looking for.

chuck eastwood

John.G wrote: »

The proposed modification looks promising as it gives a additional heat loading other than from the cylinder coil, I suppose one might say that the zone pumps should/could have wired in parallel with the stove stat originally?. and would start irrespective of what the programmer is looking for.

I was thinking about that but I wasn't sure about the wiring. I didn't want a case where I called for heat for upstairs HW from the timer, the stove pump is then starts because on the same circuitit comes on when not actually needed.
I just don't want pumps running when I don't need them so if the piping looks okay I'll try that next week.
Thanks for looking at it

John.G

chuck eastwood wrote: »

I was thinking about that but I wasn't sure about the wiring. I didn't want a case where I called for heat for upstairs HW from the timer, the stove pump is then starts because on the same circuitit comes on when not actually needed.
I just don't want pumps running when I don't need them so if the piping looks okay I'll try that next week.
Thanks for looking at it

A relay or two should prevent that but your own solution looks OK to me at any rate. What type of NR valve are you proposing to fit, is it the swing check type one?.

chuck eastwood

John.G wrote: »

A relay or two should prevent that but your own solution looks OK to me at any rate. What type of NR valve are you proposing to fit, is it the swing check type one?.

Excuse the slow reply. I need something with as little resistance as possible so I'll probably choose a swing type.if the flow meets any major resistance it will just go thtough the system link

Ian OB

Speaking as somebody with an extremely limited understanding of the terminology being used above.

Would fitting a bigger expansion tank in the attic be a solution? Have a stove with back boiler, but stove is forever too big for the house. My eyes were bigger than my belly so to speak when I got it. Expansion tank regularly overflows if the thermostats in the room are triggered (when fire is lit I set them to 25C).

Fuel used is either turf, timber or briquettes.

Dtp1979

Your injector tee is piped incorrectly. But that isn’t your main problem really. Dosent the system link control box turn on zones when the solid fuel stat activates??
If not then do as John said and use a few relays yourself. It’s no big deal really

John.G

Shouldn't the injector be only installed one way, in this case to "pull" (assist) the water downwards through the coil and prevent reverse circulation with the circ pump in service.?

Dtp1979

The way it’s installed In the diagram makes no sense to me. It’s totally restricting the gravity circulation the way installed, probably why it’s banging after 40mins

slavetothegrind

this is what Dtp1979 is talking about

https://www.google.ie/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwittqeQ74PeAhWKD8AKHbbSAGIQjRx6BAgBEAU&url=https%3A%2F%2Fwww.ukplumbersforums.co.uk%2Fthreads%2Finjector-tee.41309%2F&psig=AOvVaw24SwtNtvEVR2YeUPhEfdCg&ust=1539535586231111

See the diagram

John.G

Yes but surely the circ pump is in service before very high temperatures are reached except that the pipe stat is too far away from the stove?

Dtp1979

John.G wrote: »

Yes but surely the circ pump is in service before very high temperatures are reached except that the pipe stat is too far away from the stove?

Yea but you can’t rely on the pump

John.G

My EIR broadband is giving trouble so i cant get up a picture of the injector T but i didnt think there was much restriction in water flow from the cylinder coil or whatever in that part of the injector, the venturi effect is then produced by the nozzle inside through which the pump discharge flows.

I can't see this but I think there is a reasonable explanation here.... http://www.stovefittersmanual.co.uk/articles/injector-t-and-radiators/

another one.. http://www.torrens.org.uk/HowTo/Injector/

chuck eastwood

Dtp1979 wrote: »

Your injector tee is piped incorrectly. But that isn’t your main problem really. Dosent the system link control box turn on zones when the solid fuel stat activates??
If not then do as John said and use a few relays yourself. It’s no big deal really

Half my problem is system link didn't do a control box when this was originally installed. I used contractors on each pump and the horstman 3 channel timer for switching on/off zones.
As it stands the stove circulating pump comes on but none of the zone pumps. I'll probably have to bite the bullet and get my sparks to connect the top floor zone to pump when the stove pump kicks in.
Also i got my mate back to explain how he piped the injector T and it is as you guys suggest it should be. I drew it arseways.

Empty house over the weekend so I made the piping changes as suggested but the only none return I could get local was a spring return. Sure enough as I thought, the flow wasnt strong enough to open it allowing flow to dissipate heat upstairs. I'll change the non return to a flap and failing that I'll just pay the sparks

John.G

chuck eastwood wrote: »

Half my problem is system link didn't do a control box when this was originally installed. I used contractors on each pump and the horstman 3 channel timer for switching on/off zones.
As it stands the stove circulating pump comes on but none of the zone pumps. I'll probably have to bite the bullet and get my sparks to connect the top floor zone to pump when the stove pump kicks in.
Also i got my mate back to explain how he piped the injector T and it is as you guys suggest it should be. I drew it arseways.

Empty house over the weekend so I made the piping changes as suggested but the only none return I could get local was a spring return. Sure enough as I thought, the flow wasnt strong enough to open it allowing flow to dissipate heat upstairs. I'll change the non return to a flap and failing that I'll just pay the sparks

Just to be clear again on your objective.....you would like the cylinder + upstairs rads to dissipate the heat generated in the boiler section of your stove without bringing in the stove pump with a medium fire lighting.??

I don,t know what output (to water) the stove has but if one assumes 12KW with a full fire and say 5 KW at a medium fire then the cylinder alone might be able to absorb this if cold but once it heats up or is already hot from the night before then the coil will probably only absorb ~~ 1 KW mainly because of the very low gravity circulation flow rates, the circulating head generated due to the differences in densities is very low, for example, if the flow temperature was 95C and the return only 15C (with a "freezing" cylinder) and assuming a 5M head between boiler center and coil center then the circulating head, by my calcs would still only be 0.048M or ~< 2 ins, not a lot. The swing check check NR will help. One way or the other, if the cylinder coil is only absorbing 1 KW then the upstairs rads must then absorb ~~ 4 KW, IMO a fairly stiff task with gravity circulation alone.

I'd love to know the experience(s) of someone with just say a 12KW solid fuel boiler alone, or a dual system without system link, and if they run it, just the cylinder + upstairs rads only with a medium fire lighting and no circ pump on then will the cylinder+rads absorb this 5KW stove output?.

chuck eastwood

John.G wrote: »

Just to be clear again on your objective.....you would like the cylinder + upstairs rads to dissipate the heat generated in the boiler section of your stove without bringing in the stove pump with a medium fire lighting.??

I don,t know what output (to water) the stove has but if one assumes 12KW with a full fire and say 5 KW at a medium fire then the cylinder alone might be able to absorb this if cold but once it heats up or is already hot from the night before then the coil will probably only absorb ~~ 1 KW mainly because of the very low gravity circulation flow rates, the circulating head generated due to the differences in densities is very low, for example, if the flow temperature was 95C and the return only 15C (with a "freezing" cylinder) and assuming a 5M head between boiler center and coil center then the circulating head, by my calcs would still only be 0.048M or ~< 2 ins, not a lot. The swing check check NR will help. One way or the other, if the cylinder coil is only absorbing 1 KW then the upstairs rads must then absorb ~~ 4 KW, IMO a fairly stiff task with gravity circulation alone.

I'd love to know the experience(s) of someone with just say a 12KW solid fuel boiler alone, or a dual system without system link, and if they run it, just the cylinder + upstairs rads only with a medium fire lighting and no circ pump on then will the cylinder+rads absorb this 5KW stove output?.

My main objective is keeping power consumption to a minimum via pumps and using the water heated in the stove without having to switch on two pumps ( stove circulating and a zone) . So I was hoping the change I made to the piping would allow the stove circulating pump alone to continue to feed the systemlink and also allow some flow to the upstairs zone via the new pipe link with the non return.
Its a Stanley lismore with an output of maybe 12 to water and 4 max to room. The hot water cylinder is about 1M from the stove piped with 1 inch

John.G

chuck eastwood wrote: »

My main objective is keeping power consumption to a minimum via pumps and using the water heated in the stove without having to switch on two pumps ( stove circulating and a zone) . So I was hoping the change I made to the piping would allow the stove circulating pump alone to continue to feed the systemlink and also allow some flow to the upstairs zone via the new pipe link with the non return.
Its a Stanley lismore with an output of maybe 12 to water and 4 max to room. The hot water cylinder is about 1M from the stove piped with 1 inch

Thanks, I get it now (should have before), the swing check NR should certainly help to achieve what you want, what type of stove circ pump is fitted, if its A rated then it may be set to proportional pressure control, if the swing check doesn,t achieve your objective then changing to constant curve may help but you would want to be careful that it doesn,t result in pump over into the header tank with any combinations of systems in use.

chuck eastwood

John.G wrote: »

Thanks, I get it now (should have before), the swing check NR should certainly help to achieve what you want, what type of stove circ pump is fitted, if its A rated then it may be set to proportional pressure control, if the swing check doesn,t achieve your objective then changing to constant curve may help but you would want to be careful that it doesn,t result in pump over into the header tank with any combinations of systems in use.

The pump to on the stove is a Tucson 25 GPD 25-5S, it's an standard pump but only 4 years old with very little use. I'm changing the pumps one by one to the
Wilo Yonos PICO 25/1-6-130 Glandless. Have one on the upstairs zone now as the old Tucson flow was to high. Could hear it rushing through the pipes

John.G

chuck eastwood wrote: »

The pump to on the stove is a Tucson 25 GPD 25-5S, it's an standard pump but only 4 years old with very little use. I'm changing the pumps one by one to the
Wilo Yonos PICO 25/1-6-130 Glandless. Have one on the upstairs zone now as the old Tucson flow was to high. Could hear it rushing through the pipes

Re the spring loaded NR valve, I came across some test I carried out a few years ago on one of these and the opening head required was ~ 0.3/0.4M. I suppose the system link is the easiest path.

I find it difficult to understand the system link manifolding properly but as the zoning is done in your case with circulating pumps only, even with just the stove pump in service and no zone pumps in service why isn,t there some circulation at least through the ground floor rads via (through) the the circ pump, then the the rads and back to the system link inlet manifold?, or is there a NR valve there somewhere as well?.
http://www.systemlink.ie/uploads/6/6/4/9/66499753/systemzone_manifold-general_information.pdf

chuck eastwood

John.G wrote: »

Re the spring loaded NR valve, I came across some test I carried out a few years ago on one of these and the opening head required was ~ 0.3/0.4M. I suppose the system link is the easiest path.

I find it difficult to understand the system link manifolding properly but as the zoning is done in your case with circulating pumps only, even with just the stove pump in service and no zone pumps in service why isn,t there some circulation at least through the ground floor rads via (through) the the circ pump, then the the rads and back to the system link inlet manifold?, or is there a NR valve there somewhere as well?.
http://www.systemlink.ie/uploads/6/6/4/9/66499753/systemzone_manifold-general_information.pdf

Interesting info on the head require to open the spring valve. I picked up a swing non return today and I'll fit it over the next week. Pain having to drain most of the system again but sure two hours and I'll fire it up.
As for your question about why there isn't some flow through the downstairs zone. First of all the flow has a clear unobstructed circuit through the boiler/systemlink and cylinder coil. Any zone due to the length of pipes rads bends and pump impeller is one big obstruction creation more resistance the the stove/SL loop. Fluid will always take the path of least resistance

John.G

chuck eastwood wrote: »

Interesting info on the head require to open the spring valve. I picked up a swing non return today and I'll fit it over the next week. Pain having to drain most of the system again but sure two hours and I'll fire it up.
As for your question about why there isn't some flow through the downstairs zone. First of all the flow has a clear unobstructed circuit through the boiler/systemlink and cylinder coil. Any zone due to the length of pipes rads bends and pump impeller is one big obstruction creation more resistance the the stove/SL loop. Fluid will always take the path of least resistance

Ok.... I saw somewhere else where they show that each zone has a NR valve on the return of each return so this will further increase the resistance. The reason for the NR valve on the upstairs zone flow side is to prevent thermo syphoning, if there is a NR ( and if its a poppet type) on the return as well then that will make it more difficult for your design to work?.

The way I see it regarding the manifold is that the hot channel is common to all the flow "suppliers" and "users" and the return is common to the "suppliers" but the return channel has a inserted "auger" which effectively segregates the zones ("users"), there is also a internal bypass, they recommend using the pump on fixed speed/constant curve on the boiler/solid fuel boilers but have no problem like you in recommending variable differential head on the zone pumps.
NOW, if you had had used zone motorized valves instead of pumps then I assume that system would work without changing solid fuel/boiler pump heads?. you have a 5M pump which is fairly hefty, so the only difference now in the system is that the "stopped" zone pump(s) has been replaced with a motorized valve(s) and everything works grand, this is why I still find it hard to accept that there will be no flow through the stopped pump albeit much lower.
Also, does the above mean so that you can mix and match, ie have a one pumped zone and one or two motorized valve zones.
The next I get my hands on a circ pump I will do a flow tests on it while stopped.

Edit: Spoke to system link...... told me that poppet type NR valves are fitted in pumped zone systems to provide a bit of back pressure to stop any unwanted circulation with zone pump(s) off, not needed with motorized valve zones.

So as long as there is only one system link NR valve as you show above in the flow to upstairs rads,and none on the return, then I would think that your design mod should work OK?, it will be very interesting.

chuck eastwood

John.G wrote: »

Ok.... I saw somewhere else where they show that each zone has a NR valve on the return of each return so this will further increase the resistance. The reason for the NR valve on the upstairs zone flow side is to prevent thermo syphoning, if there is a NR ( and if its a poppet type) on the return as well then that will make it more difficult for your design to work?.

The way I see it regarding the manifold is that the hot channel is common to all the flow "suppliers" and "users" and the return is common to the "suppliers" but the return channel has a inserted "auger" which effectively segregates the zones ("users"), there is also a internal bypass, they recommend using the pump on fixed speed/constant curve on the boiler/solid fuel boilers but have no problem like you in recommending variable differential head on the zone pumps.
NOW, if you had had used zone motorized valves instead of pumps then I assume that system would work without changing solid fuel/boiler pump heads?. you have a 5M pump which is fairly hefty, so the only difference now in the system is that the "stopped" zone pump(s) has been replaced with a motorized valve(s) and everything works grand, this is why I still find it hard to accept that there will be no flow through the stopped pump albeit much lower.
Also, does the above mean so that you can mix and match, ie have a one pumped zone and one or two motorized valve zones.
The next I get my hands on a circ pump I will do a flow tests on it while stopped.

Edit: Spoke to system link...... told me that poppet type NR valves are fitted in pumped zone systems to provide a bit of back pressure to stop any unwanted circulation with zone pump(s) off, not needed with motorized valve zones.

So as long as there is only one system link NR valve as you show above in the flow to upstairs rads,and none on the return, then I would think that your design mod should work OK?, it will be very interesting.

I have never seen any layout with motorized valves and I've looked at loads, mostly out of curiosity. I'm assuming the zone flow path would have more resistance than circulating through the stove/SL and or oil/SL.
On my set up the poppet NR are directly after the pump on the flow to each zone. Seems to work as designed as I have often put my hand on the non active zone pipes and they are cold.

Bigger issue. Today I fitted the swing NR to my proposed change between the stove and upstairs zone. Easy job but then.... re filling the system. Ten mins in nothing happening, went to check the small filling tank. I Stuck my hand right in the tank and into the pipe, sure enough it was after sucking in a lump of rubbery sludge, stuck right in the opening. Tried to pull it out, got half but the rest go sucked down into the pipe and lodged somewhere. System won't fill. My head is melted, wife is going nuts as we have a 14 week old baby and it's Baltic. Ugh

John.G

chuck eastwood wrote: »

I have never seen any layout with motorized valves and I've looked at loads, mostly out of curiosity. I'm assuming the zone flow path would have more resistance than circulating through the stove/SL and or oil/SL.
On my set up the poppet NR are directly after the pump on the flow to each zone. Seems to work as designed as I have often put my hand on the non active zone pipes and they are cold.

Bigger issue. Today I fitted the swing NR to my proposed change between the stove and upstairs zone. Easy job but then.... re filling the system. Ten mins in nothing happening, went to check the small filling tank. I Stuck my hand right in the tank and into the pipe, sure enough it was after sucking in a lump of rubbery sludge, stuck right in the opening. Tried to pull it out, got half but the rest go sucked down into the pipe and lodged somewhere. System won't fill. My head is melted, wife is going nuts as we have a 14 week old baby and it's Baltic. Ugh

Hope you are getting sorted out, what a dose, and systemlink is the least of your worries just now. I have never come across any systemlink reference either to using motorized valves, its possible that I miss understood what he said, he did mention that depending on the type of manifold that there are two different by pass systems one of which is spring loaded. Anyway the best of luck in getting back in action.

chuck eastwood

John.G wrote: »

Hope you are getting sorted out, what a dose, and systemlink is the least of your worries just now. I have never come across any systemlink reference either to using motorized valves, its possible that I miss understood what he said, he did mention that depending on the type of manifold that there are two different by pass systems one of which is spring loaded. Anyway the best of luck in getting back in action.

Disconnected the filling pipe which was also the upstairs return. Used a sink unblocked pump to pump air pressure into the pipe then boom, out the blockage came. Served my time as a hydraulic pipe fitter many moons ago before going into maintenance so it wasn't to difficult.

System refilled, stove fired up and pump on. As I thought the flow/head isn't strong enough to send some of the flow upstairs. It's still all going to the systemlink. Ah well, looks like I'll bite the bullet and get a sparks to wire the upstairs zone to come on with the stove circulating pump

John.G

chuck eastwood wrote: »

Disconnected the filling pipe which was also the upstairs return. Used a sink unblocked pump to pump air pressure into the pipe then boom, out the blockage came. Served my time as a hydraulic pipe fitter many moons ago before going into maintenance so it wasn't to difficult.

System refilled, stove fired up and pump on. As I thought the flow/head isn't strong enough to send some of the flow upstairs. It's still all going to the systemlink. Ah well, looks like I'll bite the bullet and get a sparks to wire the upstairs zone to come on with the stove circulating pump

That's disappointing......if the stove circ pump is OK then there should be a big flow of water through the cylinder coil as well? if there is then the flow and return in and out of the coil should both be very hot, have you felt both of them with circ pump on and off. I suppose it's most unlikely that you have a problem with the stove pump??.

Forgot to ask what speed setting is the stove pump at, if its only at 1 then increasing it to 2 or 3 just might get the upstairs rads circulating but even if it does it is far better to wire up the zone pump as that will probably only draw < 10W whereas running the stove pump at increased speed would probably increase the power consumption from ~ 50W to 70W or even 95W on speed 3.