My daughter's complained about her heating/hot water pump making a 'funny noise'.
She seems to have one of these systems installed in her 3-storey town house: tinyurl.com/y6vzmxs2
The boiler's on the ground floor and this hot water cylinder's on the top floor.
It sounds like cavitation to me, but when I've opened the bleed valve above the pump (with the system off) nothing comes out. There is pressure in the system.
I guess I've got to poke something down the bleed valve hole as it's blocked?
Another problem, is that with the heating set to off and the hot water set to off, the boiler occasionally fires and the pump's running continuously. It seems as if the system's pumping hot water around continuously in expectation of a demand, although both valves (heat and hot water) are closed. Is this normal for this type of system?
She hasn't a manual for the programmer.
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Cant help much with this but I have found many times on the motorised valves that the micro switches can stick. Those switches fire up and close down the pump as the valve opens and closes as programmed by the timer. So the system is all off but the the pump is still running. A swift knock often does the trick.
Google V3 microswitch.
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The best of luck in maintaining this. These systems seem to be favoured in new build flats etc. I can only assume that that manufacturers offered VERY goo discount deals to builders. You will be lucky to find a local plumber who undertstands them and/or is willing to maintain it - it requires a plumber with pressure vessel certification and many of the systems require an annual service of the safety pressure release valve. The installer authorised maintenance agents know they are in a strong position if the warranty is to be maintained and charge accordingly.
The key to doing any repair to it is throw out all your existing conventional knowledge and understand fully how it works (or is supposed to!).
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should read" knowledge of conventional systems"
On a system in my fathers flat it developed a leak - local plumber would not touch it- the parts were very manufacturer specific and only carried by the authorised repair agent. Nice little earner.
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In the good old daze systems often had a secondary return for hot water so that it was available instantly. Possibility??
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Looking at the specn for the picture you posted it refers to circulating pumpS - suggesting that a pump in addition to the normal ch pump is fitted. This would run to ensure hot water is readily available at the tap outlets.
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...I'm pretty sure that is meant to be the normal (only) circulating pump, looking at the pipework and components.
This might help (but only a little bit :-( )
electricaldealsdirect.co.uk/media/pdfs/Tribune%20Ins.pdf
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electricaldealsdirect.co.uk/media/pdfs/Tribune%20Ins.pdf
That does help!
If you look at the schematic on Page 3 it shows specifically the "Secondary return circuit Bronze Pump" connected to the mid point of the cylinder. The ch circuit flow- return connections at the bottom assume that the ch pump is remote to the cylinder, colocated with the ch installation?
Last edited by: sherlock47 on Fri 28 Sep 18 at 09:17
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...a secondary circuit might account for a pump (the bronze pump) running 'unexpectedly', but, AFAIK, this should be entirely independent of the boiler (which might eventually fire up and open the appropriate valve due to hot water demand, but this isn't what the OP describes)
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I can read it the other way :)
>>>Another problem, is that with the heating set to off and the hot water set to off, the boiler occasionally fires and the pump's running continuously.<<<
I suggest OP asks daughter where the pump is that makes a funny noise.
Last edited by: sherlock47 on Fri 28 Sep 18 at 11:18
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There's only one pump that I can find. I've heard the noise she describes and it sounds like cavitation to me. The diagram on page 15 of the link supplied by tyrednemotional is exactly the layout she has.
I opened the bleed valve, but nothing (air or water) came out. The diagram refers to it as item number 11 Manual Bottle Air Eliminator.
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Much depends on the design of bottle valve, but my experience of them (or automatic ones at least) is that they only bleed air, and then close, inhibiting any water. Hence, if there is no air in the system at that point you may not get anything if you open the bleed valve.
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diagram 15 explains all - just out of interest since the filling loop is on the tank where is the pressure gauge for the sealed ch boiler system? Is the pressure being shown correctly and is it maintained? Is there pressure vessel on the boiler circuit - although it may be integrated into the boiler (casing)?
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There appears to be two pressure vessels at the top of the cupboard the tank is located in. A red one, with a pressure gauge in the pipe leading to it and a white one. I can see the red one is in the heating circuit, but I can't figure out the point of the white one.
The pressure reading is between one and two bar.
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If its got two pressure vessels it might be the water pressure tyeo system, not the fully presurised system
Either way its unlikely to be cavitation noises, pressurised systems rarely cavitate at the pump.
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The white one is a Hot Water expansion tank.
Ignoring the fact that it's an unvented cylinder, the boiler side is just a std sealed S plan. As Zero says, it's unlikely the pump is cavitating (but not impossible, see below!) - it always noisy? My guess is that the pump is knackered. How old is the system?
Something else is not right however.... once the heating and HW demand has been met (or the programmer switches it off) the pump and boiler should turn off. Has it always run on, or is it new behaviour? If it's always done this, then it's not wired up right. If it started doing this recently, combined with the pump being noisy when the demand is met, then it's possible one or both of the 2 way valves is faulty, and is closing when the demand is met, but is not cutting the power, in which case the pump could be sucking against a dead leg, and could be cavitating.
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>> Either way its unlikely to be cavitation noises, pressurised systems rarely cavitate at the pump.
If you look at the diagram, the bleed valve is directly above the pump and if a surplus of air is in the system then wouldn't it eventually reach the pump?
Daughter's reported the sytem's quieter since I opened the bleed valve and got nothing out. Next step is to isolate the power to the boiler for a couple of hours and poke something down the bleed valve - It's a pressurised system and HOT.
I'm also trying to research the programmer, but without any information on its model number I'm struggling to identify it. I'll persevere.
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Is the heating system definitely pressurised? We’ve got a large mains pressure cylinder for the hot water, but the heating is a vented set-up with a header tank. When it first kicked in earlier in the month the pump made a right racket, and in fact the boiler cut out because of insufficient circulation. It tuned out that there was a lot of air ‘trapped’ in the pipe work (which admittedly is a little convoluted) between the boiler, the three port valve and the pump itself. Whilst there’s self bleed valve in the vicinity it either wasn’t working or wasn’t up to the job. Usually it’d end up at the highest point in the system eventually and be easily be bled out of an upstairs radiator. Not this time, but a bit of hose pipe and the plumber soon had it sorted. Though, if you ask me, it still sounds a little noises than it should...
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The OPs link is very similar to what I have in my house. Installed in 2010.
Main thing for us was to be able to run two showers simultaneously from the tank and it does that well.
Have never had any tank related issues. Only boiler and valves
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hot water/central heating - Fullchat
