Towel Rad in a Gravity/Tank fed system

[lawsonium]

Hello,

This may have already been covered but I have searched to no avail so please bare with me.

I have a gravity/tank fed system which currently comprises of a Villager boiler stove which is connected via 28mm pipe to an indirect cylinder about 3m directly above. This in turn is fed by a header/expansion tank in the loft another 1.5m above that.
This works very well and really heats up the water very efficiently.

What I want to add to this system is a heated towel rail (ladder type). I have already Tee'd a pair of 22mm pipes with gate valves ready for this. These will need to be run under the flood boards about 4m to the bathroom.

I want to make sure I install the rad itself correctly.

Am I right in thinking that the best (possibly only) way to feed the hot water is at the top of the radiator, cold coming out the bottom?

If this is the case, how do you bleed air from the system?

I'm imagining a setup where both pipes (feed and return) come up from the floor, return attached to the bottom and feed travels up the height of the rad and then via two 90 elbows entersthe top of the rad.
I'm confused as to how you release trapped air from this 'high point' in the system?
Most DIY shop radiators only come with one fitting on the top which I imagine is intended for the bleed valve. Even if I could get hold of aradiator with two fittings at the top, the bleed valve would still be lower than the high point of this branch of the system (i.e. the top of the two 90 degree bends).

I hope I have described this clearly and someone on here can share some of their knowledge and expertise.

Kind Regards,

Matt.

 

[justlead1]

Hi. Why not branch off the vent pipe serving the primary flow in the roof space, run across the loft and drop into the top of the rad/towel rail with the flow and the return as you described. (the greater the circulating height the better the circulation. ) God Luck

 

[lawsonium]

Good point. Unfortunately, not that practicle. Attic space is a very cold and awkward solution. Not impossible but not ideal.
Even so, wouldn't I still have the problem of a 'high point' in the system with no bleed valve or would it be a slight fall in pipe level from the Tee?

Back to my original point though, does the rad HAVE to be fed from the top or is it completely feasible to feed from the bottom as with a pumped system?
What difference does this make to the efficiency?

Cheers,

Matt.

 

[rod A]

Hi, think Justlead1 has the right idea, the other problem you might cause is a short cuicuit of dhw cylinder causing poor hot water recovery. cheers Rod A.

 

[lawsonium]

Hi,

dhw?
Is that Direct Hot Water?

I have an indirect cylinder.

 

[NickH]

DHW = domestic hot water

 

[lawsonium]

OK, so what do you mean by 'poor hot water recovery'?

Surely the fact that this is a separate circuit it will work independently of the hot water cylinder?

Do you mean that the radiator will take too much heat out of the system and thus not heat the hot water cylinder?

Cheers,

Matt

 

[rod A]

Hi, Thanks Nick !!

 

[stevetheplumber]

it will worl with bottom connections but will work best if you feed top one from the vent near the tank and return under the floor to the return valve youve fitted