Programmer / Timer replacement on an old boiler . Pump over run needed

[Mat29a]

There's an example here. but it would need to be mounted in an enclosure.

The fan timer link that I posted earlier, see here, does the same thing but comes with an enclosure.



The timer is also controlling the boiler. So, if you were also connect a permanent live to 'C' it will also be connected to the boiler and keep it 'on' permanently. The thermostat could be wired to make use of its changeover contact to avoid this as below.

View attachment 140046

1. When the pipe is cool (the position shown in the diagram above) and the timer switches on the boiler, the pump will also start as the thermostat connects it to same switched live from the timer.

2. As the pipe heats up, the pipe thermostat contact will switch over, and the pump will now be connected to the permanent live.

3. The timer goes 'off' as does the boiler, but the pump will continue to run from the permanent live.

4. The pipe cools and the thermostat switches over back to the timeswitch live which is now 'off' and the pump stops.

Stem/heat service - this makes sense ... do you have link to a specific pipe stat model I can look at to follow up this connection? thanks

 

[stem]

Stem/heat service - this makes sense ... do you have link to a specific pipe stat model I can look at to follow up this connection? thanks

All cylinder thermostats are pretty much the same, and will have the necessary changeover contact. The Honeywell L641B you quoted earlier would be OK, but if you do use that, get the 1012 version of it that will allow you to select the 60 degrees C, setting heatservice suggests. The version of it you posted earlier is the frost protection version 1004 and doesn't go that high.

Interestingly the pipe thermostat wiring diagram I posted earlier and your diagram of the "Burgess Switch" work in exactly the same way using a changeover contact to switch the pump between the 'boiler switched live' and a 'permanent live'. The only difference is that the microswitch has its own heating device that heats up with the boiler. The pipe thermostat uses a hot pipe heated by the boiler instead. The pipe thermostat should be fitted to the flow pipe just as it leaves the boiler.

 

[Mat29a]

All cylinder thermostats are pretty much the same, and will have the necessary changeover contact. The Honeywell L641B you quoted earlier would be OK, but if you do use that, get the 1012 version of it that will allow you to select the 60 degrees C, setting heatservice suggests. The version of it you posted earlier is the frost protection version 1004 and doesn't go that high.
.

-Thanks Stem I am absorbing this gradually...Honeywell L641B 1012 pipe stat to be mounted on the hot out pipe (Y)

-Schneider Electric OFF Delay Single Timer Relay, Screw, 0.1 s → 100 h, SPDT, 2 Contacts, SPDT -this seems good but I dont understand how it fits in... it looks interesting.. do you have more info re: installing this?

 

[lfcpat]

if your going to do a job do it right. this is what you need

 

[stem]

Interesting. That uses a timer circuit to provide the pump overrun, so it's basically what was discussed earlier (before the pipe stat solution) but conveniently pre-wired and mounted in an enclosure for you. If the steel box has the same mountings as the existing timer then it would certainly make for an easy exchange.

But there's something a bit odd in that it is shown partnered with a dual channel Danfoss FP715 programmer...

..when the Horstmann it is designed to replace is only single channel, and the backplate wiring shown in the kit diagram and photo shows wiring for a single channel timeswitch (The wire loop between L and 1, and the single switching wire in terminal 3 are the clues) but it wouldn't be a Danfoss single channel model, as they use terminal 4 instead of terminal 3 that is used by some other makes.

ifcpat, who makes the conversion kit and where can it be obtained please?

 

[stem]

The diagram with the kit does help understanding some of the wiring, although it doesn't help understanding the gas valve internals. But it does identify that the wire going to MS is shown as the switched live, so it would be an easy mod to do what Old&Cold suggested earlier, which was just to swap the timeswitch function and retain the microswitch setup for the overrun circuit.

Using the Horstmann Coronet you mentioned earlier as an example (other timeswitches are available )

It would simply be a matter of connecting the new timer to the three 230V E N L boiler supply terminals, linking terminals L and 5, and then moving the brown wire from the 'MS' terminal (3) of the existing timer to terminal 4 of the Coronet. Everything else would remain in situ, but the old timer would no longer have any control of the system.

 

[Mat29a]

It would simply be a matter of connecting the new timer to the three 230V E N L boiler supply terminals, linking terminals L and 5, and then moving the brown wire from the 'MS' terminal (3) of the existing timer to terminal 4 of the Coronet. Everything else would remain in situ, but the old timer would no longer have any control of the system.

------------------------------------------------------------------------------------------------
Thanks Stem: I have just ordered the old "standard"( no pump overrun) discontinued new horstmann 424 Emerald .
As a "temporary" measure ONLY ( until I sort out a preferred pump overrun option). The new timer L & N to Boiler terminals will be directed to the boiler.
and L & N pump terminals will be wired to the old timer L-N supply-in,
with all other old connections in situ to service the microswitch. Switching the old timer on 24hrs it will serve as a temporary pump overrun.
------------------------------------------------------------------------------------------------
Do you think ifcpat conversion kit suggestion is an attractive solution/option? . just I can't yet understand the images ifcpat kindly posted.
(I have quite slow thinker and in picking up things , so always have to struggle )

 

[Mat29a]

View attachment 140169 View attachment 140170 View attachment 140171 View attachment 140172 if your going to do a job do it right. this is what you need

Thank you ifcpat for posting the photos.. would you be able to give makes models etc of the necessary units/devices to help me work out or reproduce your suggested pump overrun solution?

 

[lfcpat]

pics show elite 30 and 50 timeswitch conversion kit. simple it's a kit. I've shown it with danfoss programmer, as it was all I had to hand at the time but it is prewired for a danfoss ts715 timer, the kit as everything needed and was made by servowarm.

 

[Mat29a]

pics show elite 30 and 50 timeswitch conversion kit. simple it's a kit. I've shown it with danfoss programmer, as it was all I had to hand at the time but it is prewired for a danfoss ts715 timer, the kit as everything needed and was made by servowarm.

thanks Ifcpat...

- studying the terminals - 1 - 7 from top:, if I elaborate as I see it ( I think)
I would like to use this merely as a pump over run relay.
(the boiler will be switched from timer so can I just ignore 5-7)?)

1) L out to pump
2) - 3) permanent L/N from mains ( or timer permanent L)
4) N out to Pump

most likely need 7) from boiler ... ( red wire )

Will it be Elite 30 or 50 in this case, ( I googled and cant seem to find this kit )

many thanks

 

[stem]

I would like to use this merely as a pump over run relay.

There would be no point in doing that. The kit is designed to be installed as is as a straight swap and takes all the system requirements into account. If you start changing things, then you are back to square one and the question about the red wire.

If the kit comes without the timer, which I suspect from Ifcpat's post, that it does; then you can still use it with the Horstmann 424 Emerald you have ordered, which would be wired to the conversion kit terminals. L, N and MS.

The 30 & 50 will refer to the heat output of the boiler, 30,000 or 50,000 btu's but the literature states that the kit is suitable for both.

All of this assumes that you can still get one of course. I'm not even sure the Servowarm in question are still in business.

 

[Mat29a]

There would be no point in doing that. The kit is designed to be installed as is as a straight swap and takes all the system requirements into account. If you start changing things, then you are back to square one and the question about the red wire.

If the kit comes without the timer, which I suspect from Ifcpat's post, that it does; then you can still use it with the Horstmann 424 Emerald you have ordered, which would be wired to the conversion kit terminals. L, N and MS.

The 30 & 50 will refer to the heat output of the boiler, 30,000 or 50,000 btu's but the literature states that the kit is suitable for both.

All of this assumes that you can still get one of course. I'm not even sure the Servowarm in question are still in business.

Oh... thanks .. LOL I didnt realise it was a full timer .. ServoWarm ( "I think") was taken over probably by Homeserve, or Glow Warm?
so is a gonner so I doubt I can find one.

So it's likely be back to the drawing board.

I could remove the simple overrun unit and transfer it to the new 424,
but it is so tatty ( broke then fixed it last time when replacing microswitch) , and not worth doing.
It may be possible to rebuild this unit, using the stat plate , but the ceramic plate will be a problem to find.

the elite converter is also a long shot to find , unless Ifcpat has a spare one to sell?
so will have to stick to the original 3 options.
-pipe state,
-fan timer, and the
-Schneider Electric OFF Delay Single Timer Relay, Screw, 0.1 s → 100 h, SPDT, 2 Contacts, SPDT you suggested.

 

[lfcpat]

yes I have them to sell, but if you fit your horstman timer then you will no longer be able to close the front drop down cover. this boiler is obsolete, but I have every part you would ever need to keep it working for the next 20 years. the kit I pictured is part of what servowarm called a comfort pack, so your heating system could be updated to a y plan ie 3 port valve, timed dhw or heating. I can also supply replacement heat exchanger, gas valve, overheat stat, flow and return valves, flow and return valve service kits

 

[stem]

if you fit your horstman timer then you will no longer be able to close the front drop down cover.

Good point. Perhaps it would be possible to mount the timer outside of the boiler, and run a cable to it.

the kit I pictured is part of what servowarm called a comfort pack, so your heating system could be updated to a y plan ie 3 port valve, timed dhw or heating.

Ah. That would explain the two channel programmer then.

lfcpat, would you know how the gas valve is configured, I'm intrigued now to know the reason for the red wire, I reckon the coil will be the terminals that the capacitor is connected across, and one end of which is marked as a Neutral. The wire from MS is obviously the switched supply from the timeswitch, so I figure that the valve would be configured something like this:



The 'safety device?' is my assumption, maybe the overheat, or connected to the thermocouple? or perhaps a contact to stop the main valve opening when the valve to light the pilot light is manually open during the lighting of it. Would you be able to confirm?

Apologies for the incorrect spelling of 'capacitor' on the drawing I'm not used to writing sideways

 

[heatservice]

Question to stem: What if the Honeywell solenoid, pump & the heater coil of the bi-metal switch (pump overrun) were switched by the timer in parallel, and a permanent live powered the pump via the bi-metal swich when microswitch contact was made, would that work ? Tne overheat stat would just interrupt the thermocouple as was often the way with other makes of low water content boilers from that era.