Last rad being a nightmare to heat up, no CH when HW called as well

[Rusty89]

Morning,
Thanks to those who have helped me so far as my mission to show the missus I'm not completely useless continues.

I've got a massive radiator on the end of my open vented system downstairs. It's a double thick one, over 2m long but only about 50cm tall. It's a nightmare to heat up, even when it's the only rad turned on and pump is on 3, but it gets there eventually. When I open all 5 downstairs rads (upstairs off) it only heats the left half of the rad up which is baffling me. I've bled it and it's got x400 in at the moment. Any ideas why it's left side only?

My other question is, when CH and HW are both on, the rads downstairs (upstairs still off) don't get any heat, but the HWC heats up the water lovely. I thought this might be because it prefers to do the HWC first, but I can feel heat on both the CH pipe and HW pipes from the mid position valve (brand new valve). Where's that heat going that's shooting off to the CH?! Should I start by adjusting the HWC return valve?

Thank you, I massively appreciate your time.

 

[Madrab]

1st issue is balancing. What size of pipework is it? In essence the furthest away radiator isn't getting enough of the HW flow, you need to perform a balancing exercise. Shut off all the rads, does the large one then get hot enough?

The other issue is similar but it's a different type of balancing exercise where the flow through the coil needs to be balanced with getting enough flow to the CH circuit for all the rads.

 

[ianmcd]

you may need a restricting valve on the HW coil return, water is like us all its lazy and will always take the easiest path so if it can just fire through the coil in the cylinder it will

 

[DP]

If your timer allows, heat the water before heating so comes on line.
Obviously as Ian suggests, a valve fitted to restrict water flow into the cylinder coil, to control the excessive flow through the cylinder that in turn giving you poor flow into the radiator in question when heating and hot water is running

 

[Madrab]

you may need a restricting valve on the HW coil return

Should I start by adjusting the HWC return valve

 

[ianmcd]

yes seen that mate but wasnt sure without a pic that he actually had one, it might be a gate valve for the cold feed to the cylinder, if I fit a restrictor valve I always set it and remove the red handle so no one fecks around with it

 

[Madrab]

Yeah, for sure @ianmcd always best to confirm.

Then again even if there is one then it may not be the best thing that the OP plays about with it without knowing how to set the system up properly. Especially if the CH system isn't properly balanced either, as you know that can be a long and fiddly procedure.