22mm drop for rad on air source heat pump

[rudeboy]

I am replacing rads after an air source heat pump conversion earlier this year.

With the drop in system temp I am using bigger rads and fitting a 1600 x 600 stelrad K3 in the dining room. The 22mm feed from above will tee to feed a pair of rads in two rooms on the 1st floor and this one downstairs. The existing drop is 15mm and is only feeding this one rad. Is there any benefit to re-running it in 22mm, will this increase the flow at all, to take the 22mm pipe closer to the load? The radiator tails will be 15mm anyway via a decent trv, Drayton or Honeywell.

Cheers.

 

[Norcon]

Is there any benefit to re-running it in 22mm

No.

What kind of heat pump have you installed? (Air source I know but what model?)
These things are getting a very bad name. Almost to the point where I wouldn't take the gift of one!

You'll probably need to erect a wind turbine to help run it!

The manufacture of these devices are a novelty to the big companies like Daikin, Mitsubushi Toshiba etc as it targets a market they don't really care about. (ie - the domestic market)
The proof they don't care is in the price they charge for their domestic units.

They add a plate heat exchanger to an air source model (about £100 quid) and re arrange the piping slightly (I know because I've built commercial systems from engineers design specifications ) and then add about 200% to the asking price of an air source unit!

 

[rudeboy]

Thanks. The heat pumps are Mitsubishi, 2 x 8.5KW. Ok so far, but have not done a winter yet.
What makes you think they are so poor? Reliability, efficiency or cost?
I have no gas so these are the alternative to spending £1500 on oil. Solar PV has been a big help in the summer, though I am now watching the meter to see how the running costs work out.