Timeswitching two immersion heaters

[ringer]

Customer, sports ground changing rooms, has two 3kW immersion heaters (one for home team showers and washbasin, one for away team showers and washbasin) and has asked me to fit a timeswitch. Each immersion heater is on its own circuit, 16A MCB, 2.5mm conductors, singles in plastic trunking and 20mm conduit, and they are currently controlled via individual 20A switches. Both immersion heaters and both circuits are located side by side. Three phase supply, but both these single phase circuits are on the same phase (different mcbs).

Plan A: A single timeswitch, fed by one of the circuits before the 20a switch, to control a 4-pole contactor, to switch both circuits after the 20A switches.
Plan B: Fit an individual immersion timer on each circuit before the 20A switch.
Plan C: ???????

Plan A seems complicated to achieve a relatively simple job, and I suspect would cost more than plan B
Plan B involves setting two timeclocks
Plan C - any other suggestions?

 

[telectrix]

plan b -- 2 immersion heater timers @ £15 apiece. sorted.

 

[Guitarist]

No-brainer really mate, loads of work versus setting 2 clocks... Plus, if home team heating goes down, you can nick the clock from the away side

 

[ringer]

Customer will probably want 7 day timer. Has to be surface box-mountable. Can you suggest a make/model?

Timeguard FST17 seems to fit the bill but is £50 a pop and will need two of them!

 

[trev]

No-brainer really mate, loads of work versus setting 2 clocks... Plus, if home team heating goes down, you can nick the clock from the away side

Like it's ever going to be switched on? Yeah right

 

[Guitarist]

You can get a LAP model from screwfix for £20 each, never used them before so no idea what they are like. Personally tho, I would worry more about the quality than the cost. If you get one that goes wrong after a few months then you will be expected to sort it out.

 

[ringer]

Not too sure about the quality of those LAP ones - as you say, if they go wrong it will be me having to fix/replace. Plus they are not suitable for adding to conduit - wrong size/shape/fixings to go on surface pattress.
Prefer the Timeguard FST17 myself, but concerned customer is going to baulk at £100+ materials then a couple of hours labour on top.

 

[Richard Burns]

You would then have to go for a mechanical seven day timer that are about £30, there are some 7 day single gang mechanical timers out there.

The Timeguard digital Timed FCU seems to have the best features and other digitals are more expensive.
But if cost is king then try a Greenbrook mechanical, it will do the same job but with no isolation switch (or fuse).

Edit just thought you could fit just an immersion boost switch instead, once the team come in they press for for a 2 hour boost, end of game got hot water, then it is off until next game.

 

[Guitarist]

Not too sure about the quality of those LAP ones - as you say, if they go wrong it will be me having to fix/replace. Plus they are not suitable for adding to conduit - wrong size/shape/fixings to go on surface pattress.
Prefer the Timeguard FST17 myself, but concerned customer is going to baulk at £100+ materials then a couple of hours labour on top.

Just tell them that this is the model you are happy fitting and if they want something cheaper then unfortunately you cannot put any kind of warranty on it. Any failures within the first 3 months (or however long you warranty your work) would then result in a call out fee plus additional expense. Might make them think that what you propose is best.
If the customer is really that bothered then they could just switch the heaters on before each game and off at the end. I would just tell them it's £200 to supply and fit, job done.