Economy 7 boiler - no hot water

Hello.

Thanks for taking time to read this...

The flat in question is served by Economy 7. Currently, the storage heaters are working fine, the hot water works when on boost - but there's no hot water generated when relying solely on E7.

The tank has been fitted with new immersions and thermostats (by qualified plumber). As a test, we also switched the wiring from the boost immersion to the E7 immersion and that worked both ways, so we know the immersions are both working fine.

The wall switch in the boiler cupboard lights up when the E7 kicks in at night, so that seems okay.

The fuseboard has been checked (by qualified electrician), no trips or faulty wiring. The wiring to both the E7 immersion and the boost immersion have also been checked.

We have pressed reset on both thermostats.

If it's an electrical issue, if the E7 feed from to the flat splits (between hot water and storage heaters) when it gets to the fuseboard, then the problem can be isolated as occuring somewhere between the fuseboard and the E7 immersion connection.

If it's a plumbing issue, any ideas, anyone? We're completely out of them having, we feel, exhausted everything.

Have you checked the fuse to E7 immersion? 

Yes, Sharpend. The electrician checked that out initially.

Did he check the outputs in the switch to make sure it was live when on E7?

Yes, there's been complete circuit test done.

Is there a loose or incorrectly terminated neutral or live phase? 

Nope, polarity checks all done.

Having reread your OP I'm thinking a duff E7 switch. 

Polarity done between r1+r2, rn not checked? 

Yes, completed. R1, R2 and RN all checked.

If the wiring is all perfectly ok and you have tested the new immersion and the fuse then it can only be a faulty switch. 

Thank you so much for your input, Sharpend. Very much appreciate your time. Electrician is going back tomorrow so will keep you posted!

g2ps said:

Yes, completed. R1, R2 and RN all checked.

Click to expand...

what were the readings? 

My money is on a loose or poor connection.

Late to this discussion.

So you have checked the heaters themselves so they re okay. R1, R2 and Rn on the circuit is okay so no wiring fault

The bit that baffles me is "the light on the switch comes on when the E7 is on, so the time switch is also okay.

So one of those tests must be wrong, otherwise it would work?

The only other thing is send the spark round very late ant night or very early in the morning when the E7 is on to trace it through properly.

ProDave said:

Late to this discussion.

So you have checked the heaters themselves so they re okay. R1, R2 and Rn on the circuit is okay so no wiring fault

The bit that baffles me is "the light on the switch comes on when the E7 is on, so the time switch is also okay.

So one of those tests must be wrong, otherwise it would work?

The only other thing is send the spark round very late ant night or very early in the morning when the E7 is on to trace it through properly.

Click to expand...

or if the electrician can't or won't do that, the get him to connect a lamp of some description across the heater terminals, then ask the tenant if the lamp lit at all during the night.

Cheers, guys.

I have the sparky lined up tomorrow to do exactly that - to wire up a bulb/lamp to the E7 spur (despite this spur actually lighting up during E7 active periods. as proven by the tenant's photo of same).

Will let you know what happens...

Latest update... the electrician connected a lamp to the E7 spur on Saturday and, according to the tenant, it's been lighting up during the E7 timeframes.

So what now? Other than there being a fault with the cable from the E7 spur to the E7 immersion, I can't think what else it could be. What are the chances that this could be the problem?

g2ps said:

Latest update... the electrician connected a lamp to the E7 spur on Saturday and, according to the tenant, it's been lighting up during the E7 timeframes.

So what now? Other than there being a fault with the cable from the E7 spur to the E7 immersion, I can't think what else it could be. What are the chances that this could be the problem?

Click to expand...

Get a better electrician.

If the power is getting to the spur, yet not heating the water, and he can't find the fault, his fault finding skills are lacking.

g2ps said:

Yes, completed. R1, R2 and RN all checked.

Click to expand...

I'll try this again...

what were the readings, and were they done from the CU to the switch or to the immersion terminals?

I Dunno what to say, I get this all the time, It's never that complicated despite the E7, if everything is correct then it should work OK.

No water perhaps? 

I'm beginning to think that there definitely is no electrician involved here, either that or g2ps has much money!