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

[lfcpat]

the servowarm elite 30/50 boilers were the first to use a modulating gas valve, ie gas pressure to gas valve was reduced instead of a stat turning it off. well ahead of it's time. boilers were made by a company called Malvern boilers. early days of central heating systems in the 1970's servowarm had a cheaper way to install, no header tank required in roof space, instead they used just a tube at highest level which customer had to top up. you could put a plastic duck floating and when the level dropped the duck dropped, hence time to top up system. they next went on to make the first condensing boilers to be fitted., well before they had to be. these boilers were band B

 

[heatservice]

 

[Mat29a]

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 this boiler is obsolete, but I have every part you would ever need to keep it working for the next 20 years.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

Ifcpat I am interested in buying the elite 50 converter..
I couldnt quite grasp the whole process. can you give me baby steps illustration so my slow mind could comprehend
say how the "="s correspond with converter terminals etc
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A:-
My boiler has 3 cables ( igore Earth wires ) = to the converter image below
1) Mains supply L =
Mains supple N =
2) Pump L =
Pump N =
3) Boiler / Gas valve L =
Boiler N =
Boiler RED ( to overrun relay) =
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where would these fit in to the elite 50 converter ( say no 1-7 from top)

-------------------------------------------------------
B:
1) If I use a new 424 emerald - only single switch supply timer.. i quite prefer external mounting.
2) I am open to if you are also supplying a purpose programmer how will it integrate with the converter

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once I am clear on this , hopefully I can wrap it all up and finish the project ...

would you also be able to give me prices of the converter with programmer
probably a full price list include other parts , heat exchanger etc for the E 50.


.or please send to [email protected]
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thanks again

 

[heatservice]

the servowarm elite 30/50 boilers were the first to use a modulating gas valve, ie gas pressure to gas valve was reduced instead of a stat turning it off. well ahead of it's time. boilers were made by a company called Malvern boilers. early days of central heating systems in the 1970's servowarm had a cheaper way to install, no header tank required in roof space, instead they used just a tube at highest level which customer had to top up. you could put a plastic duck floating and when the level dropped the duck dropped, hence time to top up system. they next went on to make the first condensing boilers to be fitted., well before they had to be. these boilers were band B

Im sorry for the delay in responding to your post which I read last night but I was laughing so much I couldn't type. Im old school and a firm believer in keeping some older appliances going but with Servowarm I draw the line, they may have been on of the first boilers to modulate if thats what you call it, then a 50 year gas oven modulated in much the same way, if the boiler was B rated the the system must have been Z rated due to the complete lack of controls. I just loved the plant pot as an expansion tank with the 15mm combined cold feed & expansion pipe and I really like the way they fitted the timers & pipes to the wall with masonry nails, the best thing Servowarm did for the heating industry was: get out of it, and I never saw a duck lol

 

[Hot&Cold]

Take a tip from Allen,

Courtesy of Allen Hart

 

[lfcpat]

i think your video proves my point. the servowarm elite 50 boiler you have taken out must be at least 30 years old, i wonder if your baxi platinum will last that long?

 

[stem]

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.

Exactly. I think that is probably how it does work, except, and sorry to keep going back to this, what is the purpose of the red wire from the gas valve to the microswitch to power the pump? when it could be connected directly to the switched output from the timer as you suggest. But it's not it's connected via the red wire grrrrr.

Mat92a, a question for you please.

Could you confirm if there are just the two wires connected to the existing timer terminal (2) marked Solenoid. [ie the red wire to the valve, and the white wire to the microswitch / heater mechanism] and no other connection to anything else, including inside the existing timer; meaning that (2) is effectively solely a terminal connector for the two wires?

 

[lfcpat]

stem, the gas valve has what is called a modulec regulator, see pics

this acts as the boiler control stat. as temp increases full burner pressure 10mb is reduced instead of turning off gas valve, down to as low as 2mb. this device also controls pump overrun, hence the red wire. this is why all other ways of getting this boiler up and running will not work as the boiler was designed to. this is a bit like allen harts baxi platinum . ok it's 30 plus years old but this is part of the reason servowarm where always slagged off by the trade, they just couldn't work out how the boilers worked. remember no internet back then plus parts only available from servowarm at silly money

 

[stem]

Ah right OK, that makes sense thanks for explaining. I learn something new (or should that be old in this case) everyday. In the photos though I can only see two electrical spade connections which I guess is the coil, plus the earth screw on the Modulec. Where's the third?

 

[lfcpat]

on the gas valve

 

[lfcpat]

on the gas valve along with a neutral and earth

 

[Mat29a]

Exactly. I think that is probably how it does work, except, and sorry to keep going back to this, what is the purpose of the red wire from the gas valve to the microswitch to power the pump? when it could be connected directly to the switched output from the timer as you suggest. But it's not it's connected via the red wire grrrrr.

Mat92a, a question for you please.

Could you confirm if there are just the two wires connected to the existing timer terminal (2) marked Solenoid. [ie the red wire to the valve, and the white wire to the microswitch / heater mechanism] and no other connection to anything else, including inside the existing timer; meaning that (2) is effectively solely a terminal connector for the two wires?

Stem: yes the red wire from gas valve is connected to the existing timer terminal (2) solenoid. which then, from this terminal, a white wire
is wired to the 2nd terminal of microswitch and relayed to ceramic heating place. I have linked the actual positions with green lines between the
drawing and photo. this 2nd terminal is switched on when the boiler is cold as the stat plate is keeping the button down /on.
within a min of firing up the the plate heats up and bows outwards releasing the button, which disconnects the 2nd terninal, and simultaneous switch on the bottom terminal ( permanent L) to the pump

This simple unit with just a 3 pieces of small parts with a £2 microswitch, much less than the elite 50 converter is much more complicated and larger.
( I am not sure what Voltage or Amp output the red wire is. for the hot plate .. if it is possible to buy the ceramic plate then
it would be quite possible to build the same overrun as it is only a simple unit.) I could remove it and put it in an enclosure, but as I said
whole switch unit is tatty .... anyone knows anything of this heating plate?

 

[Mat29a]

GAS VALVE to Programmer Solenoid terminal:
I am not sure.. but I have a feeling that this red wire from the gas value maybe a DC current instead of AC ? the ceramic plate has a grey metalic conductor strip ( see image above) that heats up the stat plate next to it... Or probably the wire supplies a very low Amp AC.. anyone throw a light opon this??

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here's a whole host of burgess microswitches... many appear to have some metal plate hinged to them .. looking at any possibility of adapting them? IF there is a 'thermostatic' one
https://www.google.co.uk/search?q=micro+switch&tbm=isch&source=iu&ictx=1&fir=y4ToHnGqWrYJhM%3A%2CrHtbBsKt2iTu9M%2C_&usg=__nuWQEgoi_7TE-0N0jH3qvOhAgLc=&sa=X&ved=0ahUKEwj30q2Lr7zaAhUEL8AKHQbTCqoQ9QEI5gIwBg#imgrc=y4ToHnGqWrYJhM:

 

[heatservice]

GAS VALVE to Programmer Solenoid terminal:
I am not sure.. but I have a feeling that this red wire from the gas value maybe a DC current instead of AC ? the ceramic plate has a grey metalic conductor strip ( see image above) that heats up the stat plate next to it... Or probably the wire supplies a very low Amp AC.. anyone throw a light opon this??

---------------
here's a whole host of burgess microswitches... many appear to have some metal plate hinged to them .. looking at any possibility of adapting them? IF there is a 'thermostatic' one
https://www.google.co.uk/search?q=micro+switch&tbm=isch&source=iu&ictx=1&fir=y4ToHnGqWrYJhM%3A%2CrHtbBsKt2iTu9M%2C_&usg=__nuWQEgoi_7TE-0N0jH3qvOhAgLc=&sa=X&ved=0ahUKEwj30q2Lr7zaAhUEL8AKHQbTCqoQ9QEI5gIwBg#imgrc=y4ToHnGqWrYJhM:

The metal arm on those is just the trigger, the metal plate on the pump overrun switch is bi-metallic, which when heated by a small electric element bends and triggers the microswitch.

 

[stem]

Stem: yes the red wire from gas valve is connected to the existing timer terminal (2) solenoid. which then, from this terminal, a white wire

In that case, as it is just a connector for the two wires and there is no other connection inside the existing timeswitch, then you could wire in your new timeswitch as below, leaving the old timeswitch, and all of other existing wires, including its 230v supply in place exactly as they are. That way, the rest of the circuit doesn't change, and the pump overrun mechanism & microswitch will remain exactly as it is. You would just be changing the timer part of the circuit.

The new timer would have to be mounted on the wall at the side of the boiler rather than inside it, and whilst the old timer physically remains in place, it won't have any time control of the boiler anymore.



The conversion kit would of course, be a better long term proposition.