Grant ASHP DIY install

[sharpener]

2 hours ago, Jenki said:

How will you prove you have necessary skills?

Similar to part P, if you do the DIY route expect an additional charge to get someone in to prove it's safe. BC will not take that risk.

 

Local BC have been happy to sign off my installation of a Battery ESS to IET CoP and Part P, a lot more stuff to get your head round there.

 

Yes re D1/D2, on the existing (1996) tank the tundish is more than 600mm below the valve(s) but I will obvs fix that if I do any work on it.

 

1 hour ago, JohnMo said:

Where a heat pump valve flow can go to DHW only when energised.

 

My thinking also, it's not a classic Y-plan setup, and fails shut. 2-port valve is I agree necessary when upgrading Y-plan to UVC as here.

 

For an HP I can't see that a 2-port valve gives any better protection so IMO has no benefit and not required with usual HP config. Irrespective of whether the HP could raise the water to 100C in the first place, that is your first point of protection so now you have three.

 

Anyone got any further thoughts on the "non-self-resetting" requirement though? Typical UVC package has non-self-resetting overtemp stat (separate from the service thermostat) which also interrupts the supply to the valve. But not shown on HP schematics, where the service stat is a thermistor temp sensor in a pocket and the valve is supplied indirectly via the HP controller.

 

Edited June 18, 2023 by sharpener

[crispy_wafer]

Just looking at the electrical schematic for my Grant HP, as I'm trying to work out how many cables I need run out to the heatpump (All in the name of making penetrations and sealing up), I need a bit of help, could someone give a once over for me please?  

 

So excluding the electric supply.

 

1*3 core from Grant EP002 Interface

1*3 Core from Wiring centre 

1*2 Core from Controller

1*2 core from HW Cylinder

 

Does that seem right?

 

 

[ProDave]

54 minutes ago, crispy_wafer said:

So excluding the electric supply.

 

1*3 core from Grant EP002 Interface

1*3 Core from Wiring centre 

1*2 Core from Controller

1*2 core from HW Cylinder

 

Does that seem right?

 

That looks right.

 

The cable entry detail on the outside ASHP unit is not the best and getting multiple cables in is not easy.  It is better if you can get a length of say 12 core control cable and run one length of that from the ASHP unit to the inside wiring centre.

[crispy_wafer]

Aah yes, searching control cable brings up lots of discussions on here so thanks for that, lots to read about.  What size would you recommend?

[JamesPa]

On 18/06/2023 at 14:17, Jenki said:

How will you prove you have necessary skills?

Similar to part P, if you do the DIY route expect an additional charge to get someone in to prove it's safe. BC will not take that risk.

 

The plumbing and theory of G3 is straightforward, but there are pitfalls and ambiguity, a lot based around D1 and D2 discharge pipes.

 

 

On 18/06/2023 at 14:17, Jenki said:

BTW it would seem that a G3 certificate is not mandatory provided you have the "necessary skills" and notify Building Comtrol before starting the work (as under) and on completion of commissioning (para 77):

That's my understanding also from reading the regulations (by which I mean the building regulations 2010  - as revised by later legislation, not secondary sources).  Furthermore I'm not sure anything in the regulations says you have to have specific skills either, unless you are doing the work for someone else.  What the regulations do is mandate what the installation must achieve.

 

Furthermore a G3 certification alone (again on my reading of the regulations) does not exempt you from having to notify building control (and pay the associated fee).  To be exempt from having to notify building control you must be a member of an approved certification body.

 

Im not sure how BC can refuse to sign it off if it meets the requirements of the regulations.

Edited March 12 by JamesPa