Hot water problem, sticking valve?

Anon

I hope that someone can advise please.

We have a Potterton Suprima 50 boiler and heating system. The central heating works fine, but today the hot water has stopped working. As a result of another answer online for problem solving, I have found that hot water makes it as far as a valve just before the hot water tank (part Sunvic SZ2301) - as a test, manually releasing the valve results in the water running/water getting heated up, switching it back to automatic switches it off. This suggests that the motorised valve is not working?

On the Sunvic site, it states that the SZ2301 Actuator can be replaced without draining the system - can a novice DIYer therefore do this or do I need a plumber? The part is around £40 to buy and appears fairly accessible (if the electrics are off etc!). Also, can I safely manually switch this valve for the next few days to get the water heated up and switch it back after a short while when we have hot water (it says to be used for draining the system etc, but I assume that all the Actuator is doing is changing the value to let water through/switch it off when the tank is full of hot water? How long would be safe to leave it?).

I am holding off getting a plumber out this weekend as chances are they will need the part which they will have to order, and I can use the immersion heater for the moment if required (or use the above technique if safe!).

Many thanks

Anon

keystone

Anon wrote: »

I hope that someone can advise please.

We have a Potterton Suprima 50 boiler and heating system. The central heating works fine, but today the hot water has stopped working. As a result of another answer online for problem solving, I have found that hot water makes it as far as a valve just before the hot water tank (part Sunvic SZ2301) - as a test, manually releasing the valve results in the water running/water getting heated up, switching it back to automatic switches it off. This suggests that the motorised valve is not working?

Yesp but you need to determine if its the actuator that has failed or the valve itself is sticking. You can do that by removing the head as you have and then getting someone to operate the roomstat so that the system calls for heat, you can do the smae yourself using the tank stat. If the head operates to turn the valve for each operating condition then its not the head. It might, of course, be the tank stat itself, is it turned up high enough, do you hear it cloicking when operating it, does the actualtor work when you operate it?

On the Sunvic site, it states that the SZ2301 Actuator can be replaced without draining the system - can a novice DIYer therefore do this or do I need a plumber?

Yes you can - you do not need to call out a plumber.

Also, can I safely manually switch this valve for the next few days to get the water heated up and switch it back after a short while when we have hot water (it says to be used for draining the system etc, but I assume that all the Actuator is doing is changing the value to let water through/switch it off when the tank is full of hot water? How long would be safe to leave it?).

Yes you can, turn the valve so that the spindle is aligned approx 8 o'clock, 2 o'clock to the valve and then both DHW and CH will work. You can just leave it like that with no problems.

I am holding off getting a plumber out this weekend as chances are they will need the part which they will have to order, and I can use the immersion heater for the moment if required

If you can be sure its the head then why not get yourself out to the merchants this afternoon and get the job done yourself today?

Cheers

Myser

We used to have these and they were notorious for seizing up. With the actuator off, does the slot mechanism on the actuator turn 90° when you request hot water from your programmer/thermostat and return back when you cancel the request for hot water?

The actuator is easy to change but you will have to wire in the new one to the wiring centre.

However, it's usually the valve that seizes (metal base). To replace that, you do need to drain the system.

keystone

Myser wrote: »

We used to have these and they were notorious for seizing up. With the actuator off, does the slot mechanism on the actuator turn 90° when you request hot water from your programmer/thermostat and return back when you cancel the request for hot water?

Nice to see that you agree with me.

The actuator is easy to change but you will have to wire in the new one to the wiring centre.

Correct.

However, it's usually the valve that seizes (metal base).

Fixed it for you. However, it's [STRIKE]usually[/STRIKE] sometimes the valve that [STRIKE]seizes[/STRIKE] gets gummed up but that can often be freed up without replacement.

To replace that, you do need to drain the system.

but only as far as just below the level of the valve.

Cheers

Myser

Nice to see that you agree with me.

Not quite keystone - OP said it was the hot water valve that was sticking.

keystone: You can do that by removing the head as you have and then getting someone to operate the roomstat so that the system calls for heat

They would need to turn the cylinder stat or hot water programmer override.

Anon

keystone wrote: »

Yesp but you need to determine if its the actuator that has failed or the valve itself is sticking. You can do that by removing the head as you have and then getting someone to operate the roomstat so that the system calls for heat, you can do the smae yourself using the tank stat. If the head operates to turn the valve for each operating condition then its not the head. It might, of course, be the tank stat itself, is it turned up high enough, do you hear it cloicking when operating it, does the actualtor work when you operate it?

I haven't dismantled anything yet - there is a metal slider on the top by sliding it fully to the other side (the top says to be used for draining or filling the system only) then the water starts running and the boiler kicks in. The Central Heating system works fine, so not sure that it uses this valve? Are you suggesting detaching the Motorised Actuator from the valve and then seeing if it kicks in when switching the hot water on?

From what you are saying, if the actuator moves round when the boiler is on, that suggests it is the valve itself -would WD40 or similar work on the valve to release it or would it need replacing?

Yes you can - you do not need to call out a plumber.

Great, every little helps, particularly if I have solved the problem!

Yes you can, turn the valve so that the spindle is aligned approx 8 o'clock, 2 o'clock to the valve and then both DHW and CH will work. You can just leave it like that with no problems.

There is nothing to turn - it slides (or do you mean with the Actuator removed)?

If you can be sure its the head then why not get yourself out to the merchants this afternoon and get the job done yourself today?

I am never 100% sure about anything, but know that hot water makes it as far as the valve (hot before/cold pipe after) and switching the valve to "always on" results in the hot water getting into the tank, which I think narrows it down to the actuator or valve.

If it is the valve itself, I think I would need a plumber as it would require draining the system and pipework which I could probably mess up . If the actuator, will need to leave until Tuesday as the plumbing dealers all appear closed round here today.

Many thanks

Anon

PS - If I left the valve permanently open, would something else on the system kick in to switch the boiler off when the hot water tank was full of hot water?

keystone

Myser wrote: »

Not quite keystone - OP said it was the hot water valve that was sticking.

Agreed but as I don't have time to google for whether the actuator part number given is for a two port or a three port valve I've assumed it's a three. That assumption might be in error, of course.

They would need to turn the cylinder stat or hot water programmer override.

Yes I know, I said that too.

Cheers

Anon

Myser wrote: »

They would need to turn the cylinder stat or hot water programmer override.

Where are they located please (sorry for newbie questions, I was proud of myself finding the hot water tank itself and everything else since then has been a bonus ).

Anon

Myser

The tank stat will be attached on your hot water tank - it will have a temperature dial on it.

The Programmer is where you set the times when the system switches on and off and will probably be located somewhere near the boiler.

There should be a hot water override/boost function on the programmer.

Anon

Thank you for your advice. It is surprising how long you can get by using the emergency solution of switching the valve to constant . Mrs Anon was not as impressed as the odd ocassion without any hot water focused the mind ... So finally got the part replaced - picked it up for £30 for a new part (eBay) and quite quick and straightforward to install as only needed the actuator not the valve. All working fine now.

One recent annoyance is on the living room thermostat (Potterton PRT2). It has a turn dial for temperature and a green light (Below), Red light (Reached). To get the boiler to kick in you have to turn the temperature down and then back up so the thermostat clicks. However, recently it hasn't always clicked on or it has clicked and then a dim red light has come on (even when room feels quite cold). It sometimes then takes a few attempts to get it on. Does the faint light mean anything or is it faulty?

Many thanks

Anon