Anyone knows where I can get a Randal 3033 Timer Controller.

[Benny5]

Please bear with me on this.
From the earlier values posted I had concluded the H/W value was indeed the problem. I was just looking for some confirmation before I change out the unit as it is in a fairly inaccessible location. I just thought there may be some standalone test, say for continuity to prove the faulty (sticking) microswitch.
Just to confirm the values captured earlier;
Programmer to CH and HW OFF
C/H and H/W stats to MIN

Brown and Blue - 0Vac. H/W & C/H
Grey to Blue - 240Vac H/W & C/H.
Orange to Blue - 0Vac. H/W, 240V ac. C/H.
Grey to Orange - 0Vac. H/W & C/H

Programmer to C/H and H/W OFF
CH and HW stats to MAX.
Brown and Blue for both valves - 0Vac. H/W & C/H
Grey to Blue - 240Vac H/W & C/H.
Orange to Blue - 0V ac H/W. 240v ac. C/H.
Grey to Orange - 0Vac. H/W & C/H

Once again many thanks for all your assistance.

 

[D_Hailsham]

Please bear with me on this.

It's my fault! I had forgotten that you had posted voltages earlier.

Just to confirm the values captured earlier;
Programmer to CH and HW OFF
C/H and H/W stats to MIN

Brown and Blue - 0Vac. H/W & C/H Both Correct
Grey to Blue - 240Vac H/W & C/H. Both Correct
Orange to Blue - 0Vac. H/W Correct, 240V ac. C/H. Wrong - due to Switch stuck closed
Grey to Orange - 0Vac. H/W & C/H No point measuring this!

Programmer to C/H and H/W OFF
CH and HW stats to MAX.

These results are the same as those above because the CH and HW are both OFF at the programmer.

The microswitch in the CH valve is definitely stuck shut.

Are you sure it is the ZAV-222 and not the ZAV-222C? The 'C' version has a replaceable actuator, so no draining down.

If you need to change the complete valve, get the Honeywell V4043H1056.

 

[Benny5]

Are you sure it is the ZAV-222 and not the ZAV-222C? The 'C' version has a replaceable actuator, so no draining down.
If you need to change the complete valve, get the Honeywell V4043H1056.

Unfortunately mine does not have the 'C' suffix, therefore its a Honeywell replacement and all the extra work. Such is life.

Off now to order one on line (Plumnation appear to be the most competitive).

All of your help greatly appreciated.

Regards,

Benny.

 

[Benny5]

I have now fitted the replacement motorised Valve and the system functions correctly except for one issue.

My set up has a non-return valve located in a loop (Tee junction) that goes from the section between the pump and the zone valves and the return to the boiler (again Tee Junction) after the H/W cylinder return, (the entire section is approx 30cm long). This valve appears to have failed as some of water from the boiler is being returned (counter to the directional arrow) via this route. For the moment I have closed the valve, this allows the water to proceed, via the respective valves, to the H/W or C/H whichever is required. Otherwise I end up recycling some of the same water through the boiler without going past either of the valves.

I have seen where these devices are used in circumstances where hot water back-flow needs to be inhibited; however, on my set up I can’t see what purposes it serves.

Can I leave it switch off or have I missed something in my understanding of how these devices are deployed.

 

[D_Hailsham]

My set up has a non-return valve located in a loop (Tee junction) that goes from the section between the pump and the zone valves and the return to the boiler (again Tee Junction) after the H/W cylinder return, (the entire section is approx 30cm long). This valve appears to have failed as some of water from the boiler is being returned (counter to the directional arrow) via this route. For the moment I have closed the valve, this allows the water to proceed, via the respective valves, to the H/W or C/H whichever is required. Otherwise I end up recycling some of the same water through the boiler without going past either of the valves.

It sounds like an automatic bypass valve (ABV). The valve is normally closed, but when TRVs (if there are any) or zone valves close down the ABV opens to provide a circulation path until the pump stops. There should be an adjuster on the valve which changes the pressure required to start the valve opening.

The arrow on the valve should be pointing towards the return.

Can you post a pic of the valve and associated pipe work?

 

[Benny5]

The arrow on the valve should be pointing towards the return.

Can you post a pic of the valve and associated pipe work?

Once again thanks for your help.

I hope the attached provides sufficient detail. If you need clearer images I can use a better camera but then that will increase the size of he attachment.

This is my first attempt at uploading on this site so I hope it works.

Regards,

Benny.
//media.diynot.com/169000_168563_35483_63506775_thumb.jpg

 

[D_Hailsham]

I hope the attached provides sufficient detail. If you need clearer images I can use a better camera but then that will increase the size of he attachment.

Larger images are always helpful, provided they are not larger than the width of the screen. The system automatically reduces them for initial display, but you can click on them to enlarge.

That looks like a non return valve, not an ABV. There seems to be a screwdriver slot on it, presumably a tap of some sort. Which way is the slot turned, along the pipe or across it?

The pipe labelled " from boiler" presumably goes into the Airjec and a pipe from there goes to the boiler.

It's difficult to work out what is going on behind the pump.

Where does the pipe which goes behind the Aerjec come from and go to?

 

[Benny5]

That looks like a non return valve, not an ABV. There seems to be a screwdriver slot on it, presumably a tap of some sort. Which way is the slot turned, along the pipe or across it?

When it's set 'along the pipe' the water feeds through the valves but also back, via this device, to the return, with the return considerably hotter than the valve feed. When set across the priority goes to the valve feed.

The pipe labelled " from boiler" presumably goes into the Airjec and a pipe from there goes to the boiler.
It's difficult to work out what is going on behind the pump.

Where does the pipe which goes behind the Aerjec come from and go to?

This is the pipe run; boiler to Airjec (this also has a feed from the header tank and an expansion to same). The pump is next in the circuit followed by the branch-off for this non-return device. After the branch-off the run continues to the two valves serving C/H and H/W. The pipe, obscured by the pump on the picture, is the return from the H/W and C/H; this has the non-return section connected. The arrow on the device point away from the return pipe (right to left as viewed on the picture).
In summary; the section with this non-return device is fitted between the pump and the control valves on the flow from the boiler to the return section after it exits the H/W tank.

On reflection, my original problem of the faulty microswitch on the valve may have contributed to this device failure, if that is what it is. As the pump was running with the valves closed thus forcing the water flow back through this device in the wrong direction.

 

[D_Hailsham]

When it's set 'along the pipe' the water feeds through the valves but also back, via this device, to the return, with the return considerably hotter than the valve feed. When set across the priority goes to the valve feed.

Then it's a crude version of an automatic bypass valve. Get it replaced by a proper ABV. The valve will normally be closed, so all the water flows through HW and/or CH valves, but when one of those valves closes or a TRV shuts down the pressure in the system will rise. The ABV then opens to allow some of the water back to the boiler. This ensures that the correct flow rate is maintained through the boiler.

Thanks for the description of the pipework. It's as I expected, but it's safer to make sure.

I don't think the "bypass" valve has failed, it's just the wrong type of valve for the job!

 

[Benny5]

Then it's a crude version of an automatic bypass valve. Get it replaced by a proper ABV. The valve will normally be closed, so all the water flows through HW and/or CH valves, but when one of those valves closes or a TRV shuts down the pressure in the system will rise. The ABV then opens to allow some of the water back to the boiler. This ensures that the correct flow rate is maintained through the boiler.

Is this the type of thing; http://www.screwfix.com/p/honeywell...g & plumbing&gclid=CPHW-KKt8qkCFYUY4Qod2252Wg

Once again I am indebted to you for your ongoing help in resolving this issue.

Incidentally this part of the system (boiler replacement) has been in place for some eighteen years. The remainder of the system, including the controls (Randall 3033 programmer and thermostat Honeywell T603A) is probably closer to 30 years old, it was old when I moved in 25 years ago.

I now need to look at replacing these. From what I've seen The Honeywell RF2 Sundial Wireless Programmer and Thermostat may be suitable. I haven't looked at the wiring implications yet.

Regards,

Benny.

 

[monoxide62]

Looks pretty much like a ball-o-fix from that pic , shutting that valve will possibly have the boiler trip on overheat.

 

[D_Hailsham]

Is this the type of thing?

That's the sort of thing I meant - you can get that model much cheaper than £35!

The remainder of the system, including the controls (Randall 3033 programmer and thermostat Honeywell T603A) is probably closer to 30 years old. I now need to look at replacing these.

Might be a good idea. You don't mention a hot water thermostat (see pic). It will be on the side of the HW cylinder. Do you have one?

View media item 10596

From what I've seen The Honeywell RF2 Sundial Wireless Programmer and Thermostat may be suitable.

You would need either the Pack 2 or the Pack 3

Looks pretty much like a ball-o-fix from that pic , shutting that valve will possibly have the boiler trip on overheat.

Presumably the installer didn't have a gate valve or ABV on his van.

I agree that it will be safer to leave it open until the OP has time to fit an ABV.

 

[monoxide62]

Only have to look @ the age of that grunfoss , ABVs were not a requirement back then nor were they widely used , if the original installer fitted the pump in that way then i agree he is a numpty , then again it's obviously stood the test of time.

 

[Benny5]

Only have to look @ the age of that grunfoss , ABVs were not a requirement back then nor were they widely used , if the original installer fitted the pump in that way then i agree he is a numpty , then again it's obviously stood the test of time.

While the original system was installed many years ago (probably thirty) a new boiler (Baxi solo RS2) was fitted about eighteen years ago and this device was fitted at the same time.

As for the device currently fitted; under normal operation how should this device operate? I would expect it to remain closed unless pressure builds up at which point it would open. Therefore, the pipe work should remain cooler on the return section. Also, which way should the directional arrow point; at the moment it is counter to the actual flow.

Regards,

Benny.

 

[D_Hailsham]

Only have to look @ the age of that grunfoss , ABVs were not a requirement back then nor were they widely used.

I agree about ABVs not being a requirement, but the OP has a Baxi Solo 2 which has pump overrun and therefore will require a bypass as the system is S Plan.

The MIs suggest an ABV as an option, but most installers would have used a gate valve or an LS valve.

if the original installer fitted the pump in that way then i agree he is a numpty , then again it's obviously stood the test of time.

For the OPs benefit, a pump should never be installed with the shaft vertical as the bearings will wear out faster. Maybe they used better bearings in those days.