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Boiler is running in short spurts of a few minutes .apart from first thing in the morning then it runs for about 15 m. rads are always around 50c once warmed up . no trv's . the furthest rad is the living room one , that's the rad i think is too small , as mark says, i'd like a double in there ,and its a single . directly above it is the rad that stays cold . i think there may be a manifold in the floor upstairs with 4 feeds in 10mm hep2 coming off it . Sounds like then the boiler is switching off on high return water temperature, the rad thats not working might be the index circuit if the valves to it are fully open and you might need to turn the others down to get flow around it (or of course it might be blocked or the valve might have failed and be stuck shut).
Either way getting all the rads to work and be hot is really important as the one in the room below will be struggling in part because the space above it is cold and therefore the heat loss to above will be larger than it should be.
Sounds like a combination of fun things to play with when its freezing cold :-)
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Dec 11, 2022 15:52:43 GMT
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Why is it that central heating always plays silly buggers when it's really cold? It never plays up in the spring or autumn?? Robert, have you tried shouting at it really loudly? or maybe threatening it with a big stick? Might make it hot
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glenanderson
Club Retro Rides Member
Posts: 4,105
Club RR Member Number: 64
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Fun On The Farm.glenanderson
@glenanderson
Club Retro Rides Member 64
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Dec 11, 2022 17:15:27 GMT
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Definitely worth retrofitting individual TRVs when funds allow. I use the inexpensive Danfoss ones from Screwfix, which seem pretty reliable.
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My worst worry about dying is my wife selling my stuff for what I told her it cost...
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Boiler is running in short spurts of a few minutes .apart from first thing in the morning then it runs for about 15 m. rads are always around 50c once warmed up . no trv's . the furthest rad is the living room one , that's the rad i think is too small , as mark says, i'd like a double in there ,and its a single . directly above it is the rad that stays cold . i think there may be a manifold in the floor upstairs with 4 feeds in 10mm hep2 coming off it . Sounds like then the boiler is switching off on high return water temperature, the rad thats not working might be the index circuit if the valves to it are fully open and you might need to turn the others down to get flow around it (or of course it might be blocked or the valve might have failed and be stuck shut). Either way getting all the rads to work and be hot is really important as the one in the room below will be struggling in part because the space above it is cold and therefore the heat loss to above will be larger than it should be.
Sounds like a combination of fun things to play with when its freezing cold :-)
return temp is 20c below feed temp , if i turn the pump down to 1 , i get 73c feed and 43c return , which is apparently too much difference . the bypass rad is the bathroom , that's warm in there, prob the warmest room . i think the totally non working rad has debris blocking the 10mm pipe to it , it bleeds cold clear water , so one pipe must be clear , also it maybe the valves to it have broken inside and i am not actually opening it , but i don't know if that can happen with a totally manual valve both sides of the rad . could be some sort of air lock i suppose ill try bleeding a lot of water out and see what happens . regards robert
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Why is it that central heating always plays silly buggers when it's really cold? It never plays up in the spring or autumn?? Robert, have you tried shouting at it really loudly? or maybe threatening it with a big stick? Might make it hot Its not too bad mark , the sitting room , with the unbaffled wood burner going was toasty on sunday watching White collar . i have not shouted at it , i have polished it , and comforted the poor old thing ,, i am surprised it works at all , it was put in in 95 , and as far as i can tell , had minimal maintenance ,, when i got here even the air inlet was blocked with dust and webs . and it was full to the brim of the flue connection with soot ,that prob fell down the chimney liner . I have never liked 10mm piping , and i think i migth have to dif up the floor in the bedroom where all the connetions are and blow down them at some point . in other news , i have a friend , nic , who ,apart from having the only rd going 5 port A series engined mini to run 120 mph in the 1/4 on road tyres ,, also knows a lot about wood burners , and he has offered to make me a baffle for the little burner , so that's very nice . also i won a 3 metre wool carpet so today i try to drive 25 miles to try to get it in the astra . which might be an adventure ..
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Dec 12, 2022 11:39:52 GMT
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That is chilly.
Snowed here last night, but cold snap is gone, for now
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Dec 12, 2022 11:50:53 GMT
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down to about -4 in Essex last night, drove back from Cambridge in a snow storm still quite a bit of snow on the ground at the moment here too.
If you shut off all the other radiators and open the valves full on the one which has poor flow it may clear any airlocks etc.
Boiler is a pretty high output with relatively few radiators probably why it short cycles. if it's an old dirty system a filter on the return to the boiler is a good idea.
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Last Edit: Dec 12, 2022 11:51:14 GMT by kevins
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glenanderson
Club Retro Rides Member
Posts: 4,105
Club RR Member Number: 64
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Fun On The Farm.glenanderson
@glenanderson
Club Retro Rides Member 64
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Dec 12, 2022 13:14:10 GMT
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Definitely worth trying to back flush that problem rad too. Shut the feed valve right down and see if it bleeds ok/clear from the return leg.
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My worst worry about dying is my wife selling my stuff for what I told her it cost...
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Dec 12, 2022 20:16:08 GMT
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Well , new data on the heating system from the kobyashi maru . i closed the balance valve end of the cold rad , and it bled cold water ,half a saucepans worth . Then opened that end and closed the valve tap end , opened the bled screw....nuffin , zip ,nada . No flow at all . so that tells me the balance valve end line is blocked .
bum.
also , i experimented with the pump speed . from what i have read i need a 20c diff between boiler out and in , well, i have, it turns out , around 30c diff , and no changing the pump to faster or slower helps .
so all this would suggest a blockage in the system , or a bad pump. or both .
so do i take it apart and take up the floor , or do i flush it with some gook ?
does flushing gook work ?
apart from that malarky , i went and got the carpet today , car was so frozen i couldn't get the doors open , so i poured cold water around the door edge , and in the end got it open without breaking the handle .
car started fine in -9c on lpg .
drove down to Clun , and the lovely lady offered me another one too , so i took both .
then down to Kington for fuel then back up country to the estate .
100 miles round trip , car went perfectly .Over the hills near presteigne it was super wintry , i had a good race with some woman in a white sleigh and long black hair,and there may have been a lion in the distance on occasion too .
regards robert
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Last Edit: Dec 13, 2022 9:25:59 GMT by ivanhoew
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Dec 12, 2022 20:41:36 GMT
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ok , got some sentinel x800 on the way .
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Dec 12, 2022 22:07:09 GMT
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Flushing gook does work well, you need to leave it in the system for a few days though.
for the car doors - get some silicone spray and spray a cloth & wipe over the door rubbers - stops them freezing to the paint.
PS, pump must be fine as all the other rads are hot and I assume it's not squealing?
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nope not squealing mark , just i should be able to get the water return within 20c of the water feed to the rads , so either its all blocked, or the pump isnt flowing as it should , i am going for all blocked .
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With the by-pass rad make sure the valve is only just cracked open, with the rad you have removed it wants the ends capping off and not looping, ive worked on a few systems that were a complete nightmare to get water in with monster air locks and have had to resort to putting a hose pipe on the mains pressure cold tap and connecting directly to the radiator valve to force the water in that way
As BP says the flushing agent needs to be in for a bit but wont do much if the waters not circulating
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Dec 13, 2022 16:54:49 GMT
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Last Edit: Dec 13, 2022 17:01:57 GMT by ivanhoew
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Dec 13, 2022 17:14:10 GMT
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Dec 13, 2022 17:29:23 GMT
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That's not optimum!!
Any chance of bodging a pressure washer on to the pipes?
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Dec 13, 2022 19:50:47 GMT
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Could you pop the 22mm T off and see if that is also blocked?
At least if you have access to the flow and return feeds to the rad you can flush it in situ with some hose pipes. If you get something like a pair of flex pipes with speedfit on one end and standard screw fix on the other you should be able to make a water tight connection as well.
I am by no means a plumber, but I have had to do a fair few bodge fixes lol
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Last Edit: Dec 13, 2022 19:51:46 GMT by joem83
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Dec 13, 2022 22:30:41 GMT
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That pipeworks bad but also good, it shows that you have something fundamentally wrong and if you get that working you may find that the existing rads are sufficent and if not that they will at least be better.
The temperature difference (delta T drawn as a triangle then T) is important because the heat output of the radiators is better the higher it is in theory but you tend to design a system so that the return temperature is correct for the heating plant (boiler) to make it most efficent and 30oC is way higher than anything i've come across, we tend to try and get around 10-20oC delta T depending on the type of system. You also need flow temperature of course and 80/60oC would provide more heat to the radiators than 70/50oC for example. Old commercial systems used to be 82/71oC
As you have said, a lower flow produces a higher delta T and a higher flow a lower one and with all that gunk in the system its not surprising you are losing a fair amount of heat but the rads are perhaps not getting that hot.
At least all being plastic you should be able to clean the pipes out, if the bends aren't too sharp you can probably rod through the pipes as a last resort.
It does seem odd though that they have used 10mm when doing it in plastic, the only 10mm plastic i've used was in the old wet underfloor heating system in the ensuite in my old house.
Looks like once you have got it cleaned out you could do with one of those magnaclean filters on the system and servicing it reguarly until the worst of the crud has come out.
Might be worth taking each rad off, taking them outside, removing the valves on each end and jet washing through them.
Just to mention that I had one in my old house where the bleed screw hole was blocked so worth checking that while its off.
Good luck :-) as an aside you mentiond Clun, about 20 years ago we replaced the main boiler room at the schoole there, its probably due another replacement soon happy days!
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Last Edit: Dec 14, 2022 0:43:17 GMT by joem83
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