Gate valve query and noisy system on old Myson Apollo

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Hello I wonder if anyone can help. I have a Myson Apollo 30/50B with a Honeywell Y plan? , it was in the house when I moved in, in 2003. I assume it was fitted in the 80's. As a diy-er since moving in I have changed TRVs/lockshields and four rads (approx 10 years ago) added wall stat and changed the clock however recently I had to change the pump, wall stat, tank stat and as I had one spare the motor on the 3 port valve and programmable clock all like for like.
The water flow has always been noisy since moving in as in water whooshing when first switched on and the sound of water going through the pipes like a stream and I can also hear what sounds like water dripping into water in the airing cupboard. My boiler is in the garage and last week I could hear a odd noise when the heating came on so checked the system (bled rads etc) and I noticed it was constantly short cycling even when first switched on, the rads heat up and the water heats up no problem however it will fire up for say 7 seconds then shut off for 15 seconds and will do this as long as its on. I havent noticed it before but I havent looked for it so it could have been doing this for a long time? it does when cold on occasion fire up and stay on for a while then switch off and cycle as normal, only when its fully at temp will it constantly short cycle.
Since changing the stats and pump its a lot hotter than its ever been. I have sort of balanced the rads using touch as a guide as no thermometer, they all seem to be working fine.
Also when I first isolated the system many years ago so I could change the rads etc I shut off all taps including two that are near the tank, its only this week I have found they may be balancing gateway valves (I genuinely didnt know thats what they could be so shut them off) Since then they have always been fully open but since I have found out what they could be and because the boiler is short cycling I have opened both one full turn and adjusted each slightly (open) to see if it stops the short cycling, it doesnt. If you look at the photos the valve on the right (not the one on the return from the tank) when I turn that down the sound of the water gushing improves.
So any ideas why its short cycling, why a whooshing noise (sounds like a low jet noise lasts about 3 seconds but continuous), why does the water constantly sound like a stream (and dripping noise) and are they two gateway valves and are they used for balancing, should both be fully open or one be closed and one open. Oh the 3 port valve seems to be working as it should but the manual lever seems loose and sometimes doesn't stay on manual. It does however divert when needed.
I have included a video, you may have to turn your volume up to hear the water.
I am intending getting it replaced this year due to government restrictions on gas boilers. I don't fancy a heat pump.
Thanks in advance

 
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I am not a plumber....

Assuming this is a Y plan system:
The 1st valve is simply a tank isolation valve. Leave it well open.
The second valve is a bypass. It allows water to cycle around the HW circuit when the boiler is overrunning and all of your TRVs have closed.
Normally, they are left open 1/2 turn or so in accordance with min boiler flow requirements. ABVs are used these days.

Set the valves as per above.

Water noise may be the velocity increasing as the system becomes restricted due to sludge.

I am happy for a pro to disagree with this though :)
 
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I am not a plumber....

Assuming this is a Y plan system:
The 1st valve is simply a tank isolation valve. Leave it well open.
The second valve is a bypass. It allows water to cycle around the HW circuit when the boiler is overrunning and all of your TRVs have closed.
Normally, they are left open 1/2 turn or so in accordance with min boiler flow requirements. ABVs are used these days.

Set the valves as per above.

Water noise may be the velocity increasing as the system becomes restricted due to sludge.

I am happy for a pro to disagree with this though :)
Thanks for the reply. I am also assuming it's a Y plan going by the wiring diagram with the paperwork I have. When you say 1st valve do you mean the one on the left next to the tank? I think you do. I will adjust as you say. I have thought it could be sluged up so was going to flush it this year either way. It's never been done since 2003, I'm guessing it's never been done since it was fitted. Thanks again
 
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Thanks for the reply. I am also assuming it's a Y plan going by the wiring diagram with the paperwork I have. When you say 1st valve do you mean the one on the left next to the tank? I think you do. I will adjust as you say. I have thought it could be sluged up so was going to flush it this year either way. It's never been done since 2003, I'm guessing it's never been done since it was fitted. Thanks again

Yes.

Vid for flushing rads if you are wondering:

I like your plumbing. Looks very tidy and neat :)
 

DP

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Thanks for the reply. I am also assuming it's a Y plan going by the wiring diagram with the paperwork I have. When you say 1st valve do you mean the one on the left next to the tank? I think you do. I will adjust as you say. I have thought it could be sluged up so was going to flush it this year either way. It's never been done since 2003, I'm guessing it's never been done since it was fitted. Thanks again

Do not get involved with flushing etc unless circulation issues have been discovered. Do you have radiators that have cold spots in the centre? If not, leave well alone, get boiler serviced properly, that will be beneficial. The heat exchanger will be well clogged on air side based on what I find.
 
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Yes, it is a Y plan. Lever on valve will be floppy when valve is open to CH side, dont worry about that. HW Temp needs to be set higher, you want it at around 65° to prevent any possible build up of Legionella bacteria.

Do you know if there is enough (any) inhibitor in the system? The first check I'd advise you to make is try a decent Magnet on the Air Separator can and adjoining pipework, any signs of it attracting?
 
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No it is not!!

Ok, if it isn't to isolate the tank coil, what is it there for? (genuine question)


If running to heat water only, end of demand why would water pass through the bypass?

I thought if 3 port valve is on CH, and TRV's are closed, the pump will dead head unless there is a bypass, or the 3 port valve changes to HW, hence the bypass.

I don't see a bypass on typical Y plan drgs but i was thinking this is because they don't allow for trv valves on the circuits?
Am i wrong?
 
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Do not get involved with flushing etc unless circulation issues have been discovered. Do you have radiators that have cold spots in the centre? If not, leave well alone, get boiler serviced properly, that will be beneficial. The heat exchanger will be well clogged on air side based on what I find.
Ok thanks. No I don't have cold spots. Since balancing the rads they all get hot as expected, I'd say 80% to 90% of the rad hot the rest, the bottom slightly cooler which I believe is normal ? Yes I agree it needs a service
 
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Yes, it is a Y plan. Lever on valve will be floppy when valve is open to CH side, dont worry about that. HW Temp needs to be set higher, you want it at around 65° to prevent any possible build up of Legionella bacteria.

Do you know if there is enough (any) inhibitor in the system? The first check I'd advise you to make is try a decent Magnet on the Air Separator can and adjoining pipework, any signs of it attracting?
Im not sure if there is any inhibitor. I'm sure the manual said don't add any additives to the system, I'll recheck unless the inhibitor is ok to add. I'll try the magnet. Thanks
 
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If there is no inhibitor in the system, there (quite probably) lies your issue. The mixture of metals in CH systems along with the water, causes a chemical reaction, which creates magnetite sludge. Inhibitor (funnily enough) inhibits this process... Not sure which manual suggested not adding inhibitor, they're wrong!

I would be very confident now your system is full of black sludge, which is blocking the pipework, hence your issues. No point putting any inhibitor in now, you need to clean the system out, and remove/replace any blocked pipework before doing anything else. Once thats done, look at flushing the system, adding a chemical cleaner, and see what that does. If performance is improved, then drain out the cleaner, and refill adding inhibitor when complete.

Do the magnet test and report back please.
 
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The second valve is a bypass. It allows water to cycle around the HW circuit when the boiler is overrunning and all of your TRVs have closed.
The bypass allows water to flow through the boiler when all TRVs are closed. That's probably what you meant, but just to be clear.
 
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The bypass allows water to flow through the boiler when all TRVs are closed. That's probably what you meant, but just to be clear.

Yea, well spotted.

That's exactly what i meant lol.


Must.try.harder.
 
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Yes, it is a Y plan. Lever on valve will be floppy when valve is open to CH side, dont worry about that. HW Temp needs to be set higher, you want it at around 65° to prevent any possible build up of Legionella bacteria.

Do you know if there is enough (any) inhibitor in the system? The first check I'd advise you to make is try a decent Magnet on the Air Separator can and adjoining pipework, any signs of it attracting?

Yes you are correct the air separator and pipe going into the pump is attracting my magnet. Also the Apollo manual does state the user should not add any inhibitor, system additive or water treatment so refers to user not fitter as it states in fitting instructions use ferrox inhibitor. As there is a blockage I'm assuming there is no inhibitor left. I can also hear most of the dripping and flowing noise through that part. So that will need replacing asap. Will that also be causing the short cycling. Also the two gate valves, the right side is obviously the balance valve but is the left one just an isolation valve and should be open fully or say half. First post above said this but another guy said it's not just an isolation. Thanks
 
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