Economy 7 - Hot water not working

jbuchanangb

I think that the whole Horstmann timing system with boost etc is connected to circuit breaker GREEN 5 which is labelled ONPEAK WATER HEATER.

There is likely a separate circuit completely for the bottom element and this comes from OFF PEAK circuit breaker No. 3

This theory could be checked by switch OFF GREEN 5. Then the timing clock on the HORSTMANN unit should stop, and nothing should happen with or without boost.

As has been said before, a unit like that Horstmann thing would normally be used where there were no separately wired off peak circuits, and an immersion heater with a single element, the operation of which needed to be synchronised to the Economy 7 off peak hours.

With that switched off, let the system run overnight to see if the new element heats up.

Gerry1

jbuchanangb said:

This theory could be checked by switch OFF GREEN 5. Then the timing clock on the HORSTMANN unit should stop, and nothing should happen with or without boost.

Nope.  The clock should continue because it has a 150-hour battery backup.  It can support single or two element systems.

Richie-from-the-Boro

+/- 40 year old e7 Quartz Horstmann water controller, done well to survive 40, usually 10-15 years.
Why upside down no idea.
Note; isolator  built into Horstmann will safely throw other circuit to SAFE/OFF.
New E7 controllers and conversion wiring pdf's on Hortman site.
Unusual to see an extra bodge on/off for 60/120 second day rate on E7 must have been bodge E10 etc at one time.

Heely

Gerry1 said:

At what time was your neighbour present?  If it was only in the daytime then the connections to the new element can't have been tested.

Presumably the lower heater has its own switch not shown in the photograph, and this has been left on?

Presumably the trunking going down from from the small square switch goes to the upper heater?

My neighbour was present during the day. Aha!
Both heaters (lower and upper) use the same water heater switch. The trunking goes to both. 

tim_p

Thermostats often have a trip / reset switch, usually a bit hard to see, might be worth looking or getting neighbour to see if it could be that. Shouldn’t be if it’s the stat supplied with the new element but if it’s the original then I’d suspect that. 

Heely

stewie_griffin said:

Try switching a storage heater on tonight and see if it charges up. If it doesn't the it's a problem with your meter or timeswitch (if it's external to the meter).

It hasn't charged since the new immersion heater was installed few days ago. 

Gerry1

Essentially there are only three possibilities.

• No supply voltage is reaching the element.  Culprits include the E7 timeswitch / contactor and strange wiring / operation of the Horstmann timer.
• The thermostat is faulty or not calling for heat.  Turn it to maximum.
  
• The element is faulty or has an open circuit connection.
  

A nocturnal test with a voltmeter (after the meter has been observed to switch to night rate) should yield results.

tim_p

Heely said:

stewie_griffin said:

Try switching a storage heater on tonight and see if it charges up. If it doesn't the it's a problem with your meter or timeswitch (if it's external to the meter).

It hasn't charged since the new immersion heater was installed few days ago. 

Wait, so when the immersion failed, so did the storage heater?? Or are you saying that it’s off anyway and nothing to do with the immersion failing?

Heely

tim_p said:

Thermostats often have a trip / reset switch, usually a bit hard to see, might be worth looking or getting neighbour to see if it could be that. Shouldn’t be if it’s the stat supplied with the new element but if it’s the original then I’d suspect that. 

Is the thermostat reset switch located on the Immersion element?

Heely

Gerry1 said:

Essentially there are only three possibilities.

• No supply voltage is reaching the element.  Culprits include the E7 timeswitch / contactor and strange wiring / operation of the Horstmann timer.
• The thermostat is faulty or not calling for heat.  Turn it to maximum.
  
• The element is faulty or has an open circuit connection.
  

A nocturnal test with a voltmeter (after the meter has been observed to switch to night rate) should yield results.

Tested - No supply voltage is reaching the element.