Draining down hot water - large UV system with circulator?

[MattWeth]

I've got to replace a shower mixer cartridge on Wednesday. While it should be fairly straightforward, it's complicated by there not being a single accessible isolator in the whole house so it means turning off the hot and cold to the entire house and draining the upper floor far enough to clear the shower in question.

It's a huge house (six bathrooms) and runs off a large UV cylinder with a circulator pump (the whole heating system is almost industrial in scale). I've never messed with a HW system this big with a circulator - is there anything I need to be aware of that might trip me up?

cheers
Matt

 

[Roger Welton]

Freezing it then fitting isolators not an option? Nothing out the ordinary I can think of, just remember to electrically isolate the bronze pump, and vent well before restarting it.

 

[MattWeth]

Freezing it then fitting isolators not an option? Nothing out the ordinary I can think of, just remember to electrically isolate the bronze pump, and vent well before restarting it.

Thanks Roger - I'll definitely be isolating the pump.

Unfortunately freezing isn't possible - all the pipework is concealed behind expensive travetine. I reckon the conversion (it was a large farmhouse) must have cost millions but some of the workmanship is shocking - wetroom floors slumping as timberwork settles so that 10mm gaps have opened up under skirting tiles, all pipework buried behind walls / above ceilings with no access, not a single pipe in the boiler room labelled (complex system, six heating zones etc).

Still on the good side, they're a good customer for me as I've been back four times so far spending full days sorting out a litany of problems

 

[Roger Welton]

Enough work to keep you busy for a bit then