Condensate transfer pump with problems

JUGHNE

I did a "ride along" to look a 1929 2-pipe system. There was a remote condensate pump to replace some leaking buried wet returns. The discharge of this is piped into a dry return. The rads connected to this dry return do not heat unless you crack open the trap caps (and get them closed before the pump cycles). This has been this way for some years. Has anyone tried a throttling device or square head cock to slow the flow down enough to allow the rad traps to drain? Or is a separate pipe the only solution.
The boiler has its own feed pump which in controlled by a 150 MD pump & low water control. This pump has a very short on time of just a few seconds. Should it have a throttling device also? Thanks for any advice.

nicholas bonham-carter

Are there any crossover traps which are not letting the air out?
I would think that condensate pump should go all the way back to the wet return, or even better replace the leaking wet returns, but above the floor.--NBC

RJ_4

Throttling is needed, You should have a circuit setter or plug cock down stream of pump, as well as a check valve, and guage
see page 172 in the Lost Art of heating book for a detailed description

JUGHNE

I believe there were main vents at the end of that dry return (the one used for the pump)
Just from my short visit it appears that to install wet returns above floor isn't feasible.
Do you believe the throttling & check valve are needed for the transfer pump and has this worked elsewhere?
The feeder pump which runs for just a few seconds has a check but not much for throttling.