Running Combi boiler without rads
- Thread starter sharpspark
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namsag
So one of the cheaper crapy manufacturers needs an external bypass ,as i said there will probably be some out there that need one. Billy Bob did say on a couple of occasions that it wouldn`t work. And by your reply to me explaining how a combi works (sucking eggs) and basically saying the boiler wouldn`t have any or not enough water in the primary circuit to work operate flow switches or transfer heat also infered it would not work.
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- 13 Oct 2003
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Thanks for all the interesting discussion! I've checked with Halstead and they are quite happy with the 4m of 22 mm pipe that will make up the total central heating system with the 2m flow joined to the 2m return at the end. The idea of just shutting off at the cocks wasn't pursued as they suggested joining flow and return and having this as long as possible. The 4m I'm using was fine. Obviously it will be filled and pressurised.
Thanks.
Thanks.
B
billy bob
It is not a case of proving people wrong, it is a case of what is right and what is wrong, this thread started with someone asking can they run the hot water on a combi without the heating side connected, we all said no as the heating side needs to be full of water to heat the hot water, or do you disagree with this BAHCO, it was also said that the boiler needs to dissipate the heat within the heat exchanger once the hot tap is turned off, to do this it will need some kind of heat sink
You say your boiler is a Vaillant well try contacting them and tell them that you want to run your boiler temporally the way you said you have, I bet I know what the answer will be
The professionals on this site give the correct advise, we only suggest the correct way of doing things, if your boiler worked with just the small amount of water that would of been in the boiler if you only filled the heating side within the boiler, you would of put the boiler and pump under excessive heat and if Vaillant were aware you would certainly lose the warranty on the boiler
You say your boiler is a Vaillant well try contacting them and tell them that you want to run your boiler temporally the way you said you have, I bet I know what the answer will be
The professionals on this site give the correct advise, we only suggest the correct way of doing things, if your boiler worked with just the small amount of water that would of been in the boiler if you only filled the heating side within the boiler, you would of put the boiler and pump under excessive heat and if Vaillant were aware you would certainly lose the warranty on the boiler
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billy bob
Exactly sharpspark that is what we have all said, you need some sort of circuit to dissipate the heat
If only would read the replies fully, no one has said that you cannot run the boiler without the heating side connected only that a circuit needs to be in place to dissipate heat
The only time I said it will not work is when how I read the post it was said that the hot water side could be run without water in the heating side
If only would read the replies fully, no one has said that you cannot run the boiler without the heating side connected only that a circuit needs to be in place to dissipate heat
The only time I said it will not work is when how I read the post it was said that the hot water side could be run without water in the heating side
B
billy bob
namsag, cheap and cr*ppy, so what make of boiler do you think is a good make then
N
namsag
The three main manufacturers Vailant ,worcester cdi range and Baxi with the 80e and 105e (not the instant) a very reliable boiler for only £477 +(105e) all sold through proper merchants unlike ravenheat which are sold through BQ purely on price and aimed at the diyer who don`t know any better. would not touch ideal at present as one is a biasi (cheapest of the cheap) and the the other is still having problems after a couple redisigns. Why what do you class as good is it what you can make the most money out of installing or what is going to benefit the customer in the long term regards easy cheap repairs if it should go wrong and people willing to work on it.
So in a nutshell you can run the boiler with the flow and return off BUT you risk damaging the boiler due to no heat dissapation. The installer did not tell me this and I am grateful for the advice 
.
Many thanks
.Many thanks
i have done it myself and it worked ok
has nobody ever ran a combi with the service valves closed to prove a faulty diverter?
has nobody ever ran a combi with the service valves closed to prove a faulty diverter?
If the diverter valve is faulty i.e. not diverting the water to secondary heat exchanger, isolating flow and return at the service valves will only result in pumping to a dead end (bypass loop ignored as it may or may not be there).
One cannot make a broad statement that it is OK to run a boiler with isolating valves closed. In every case I would want to refer to the MI to ensure no permanent failure will result if one has to go down this route.
There are heating engineer and there are heating engineers. Went to a boiler last week that had a diverter, thermocouple, overheat stat and more replaced in a blind effort to repair a defect. In the end the defect still remained uncleared as boiler operation was not understood. I am sure the diverter had been replaced before because the replaced diverter was besides the boiler and it looked new (bright metal).
One cannot make a broad statement that it is OK to run a boiler with isolating valves closed. In every case I would want to refer to the MI to ensure no permanent failure will result if one has to go down this route.
There are heating engineer and there are heating engineers. Went to a boiler last week that had a diverter, thermocouple, overheat stat and more replaced in a blind effort to repair a defect. In the end the defect still remained uncleared as boiler operation was not understood. I am sure the diverter had been replaced before because the replaced diverter was besides the boiler and it looked new (bright metal).
totally agree but if the diverter is passing to the heating then closing the valves restores the hot water
proving the fault
like i said have done same on a ferroli worked lovley 3 years ago still was last week
not trying to be clever but it can be done
proving the fault
like i said have done same on a ferroli worked lovley 3 years ago still was last week
not trying to be clever but it can be done
Which ferroli are you talking about?
Most Ferrolis (that I have come across) do not have a diverter valve. Heat exchanger is a twin pass that does not require a diverter. Furthermore, the pump does not run when HW is demanded. AND the pump can run if residual heat present in the heat exchanger (to be dumped in the radiators) with pumped water not going anywhere with service valves closed.
Most Ferrolis (that I have come across) do not have a diverter valve. Heat exchanger is a twin pass that does not require a diverter. Furthermore, the pump does not run when HW is demanded. AND the pump can run if residual heat present in the heat exchanger (to be dumped in the radiators) with pumped water not going anywhere with service valves closed.
what i said was closing the service valves proves the diverter is passing
didnt say it was a ferroli that was a different job
didnt say it was a ferroli that was a different job
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