Basic questions about Central Heating System

thomas the tank engine

Hi Guys,

First post on a social media site ever - lol.

Have some BASIC questions wrt central heating system.

Q1. Regarding the valves

My understanding is that the lockshield valve regulates flow ( and therefore heat ) What does the other valve do? ( its not a TRV - just look like the lockshield)

Q2. Boiler Pump pressure read out appears to be at 0.5 bar and sitting on the red line/segment of the dial. Anyone know what rating the pressure should be at for this model - or is that a variable depending on how the system is balanced?

To put these questions in context I poorly performing radiators downstairs - they heat up to about 50C as opposed to 60C upstairs. They also take much much longer to heat . I tried opening up lockshield valves downstairs and closing them to within 1/2 turn from closed upstairs. No difference.

I am thinking I will close all lock shield on rads upstairs and fire up the boiler to see if I get 60C heat downstairs... if this does not result in 60C heat then what? Could I have a problem with an nonperforming pump or is my system not heating the water hot enough full stop ( should I be getting more than 60C?)

All of the radiators are bled . The temperature gradient across flow and return for each rad is at about 13 C for all but one ( 20C in kitchen - last on loop )

I do tend to get air in the system with small bathroom rads upstairs tending to go cold due to air blocks from time to time. ( I have never bled the pump. ...)

System is about 16 years old .
Boiler is a Potterton Prima F50 model.

Cheers,

TTTE

thomas the tank engine

Hi Guys,

I managed to get all radiators up to approx 60C by following the loop and opening up the lock shield valves wider as the circuit returned to the boiler. They are still slower to get up to heat downstairs and upstairs get a couple of degress warmer. The average temp off the radiators after 20 mins is 60C - should I expect more? I looked at the Potterton Prima F50 manual and I believe the unit can supply up to 82C. However I can't measure the temp out directly out from the boiler as I just can't get to the pipe with the infrared thermomter.

So my question now is.

1) Should I expect more than 60C from the radiator from a system like this? Or is this about right effciency wie given the model and its age?

Important: I noted on my last run that the boiler pump dipped to about 0.3 bar - firmly into the red ( warning starts at 0.5 bar which is where it sits before the system is tunred on ) I assume i have an underperforming pump which shows up big time after I balance and get all rads into the cct. I assume this has some bearing on heat delievery? ( 20 mins to get to 60C seems slow and underperfoming)

Before changing the pump should I consider bleeding the pump / topping up my system with more water?

I am learning as I go here Any thoughts greatly appreciated.

Thanks

TTTE

Water will always take the path of least resistance hence the need to balance the system so you have even heat distribution, but there are other factors.

As you mentioned your pump could be having a negative impact but you can't rule out boiler settings/components, sludge or system design.

If I were you I'd find your friendly neighbourhood gasman to service the boiler and who would be happy to talk you thru any requirements to get your heating system working right.