Weil McLain Ultra 310 boiler circulating pump location

Nestor1

Hi Guys:

Back in 2006 I had the circa 1960 Anthes boiler in a small apartment block replaced with two Weil McLain Ultra 310 Series 2 boilers.  The installation manual for multiple boilers wasn't explicit on where the Taco 0014 boiler circulating pumps should be located, but all of the piping drawings showed it to be on the supply piping from the boiler so that it was pumping hot water out of the boiler.  The heating contractor that installed the heating system followed that lead and installed the boiler circulating pumps on the boiler supply piping.

Weil McLain has since changed their position on the matter.  The installation manual for a single Ultra 310 Series 2 boiler says warns that the boiler's circulating pump should be installed as shown in that manual or the result could be nuisance shutdowns as a result of insufficient flow through the boiler.  And, all the piping diagrams in the single boiler manual show the boiler pump to be on the return piping to the boiler, so the pump is pumping cold water into the boiler.

Well, wouldn't you know it.  Since those two boilers were installed in 2006, I've been having "B 30" soft lockouts on both boilers.  The error code B 30 means that the water temperature increase across the boiler was too high, and the boiler shut itself off on a soft lockout because it thought something was wrong.  So, the boiler would cool down, and then fire up again, and this "Knock yourself out" dance would continue indefinitely.

I have since been able to eliminate the B 30 soft lockouts by turning down the fan speed on both boilers.  These boilers draw their fuel gas in through a venturi, so the faster the air is being blown into the boiler, the more fuel gas gets drawn in with that air.  By turning down the maximum fan speed, the boilers draw in less fuel gas and produce less heat and that prevents the soft lockouts.

The problem is that with the reduced maximum fan speed, the boilers don't produce enough heat to meet the heating demands on the coldest days and weeks of the winter, and I'm subsidizing the cost of my tenants running electric heaters in their apartments.

I've been told by the head of the heating department at my local plumbing wholesaler that since they started installing the boiler pumps on the return piping, they haven't had any problems with the B 30 soft lockouts.  So, I am considering spending another pile of money relocating the boiler pumps onto the return piping, relocating the boiler LWCO's to the supply piping, and all of that is going to require that I also move the gas supply piping and electrical junction boxes.

Has anyone in here had experience correcting Weil McLain Ultra 310's giving B 30 soft lockouts, and has anyone any first hand experience that these problems were corrected merely by moving the pump from the supply piping out of the boiler to the return piping into the boiler.

Any help in this matter would be greatly appreciated.

Nestor

M Lane

Manifold?

How did the manifold get piped? Primary/secondary, reverse return, first in/last out?

When you go primary/secondary, the primary loop pumps are on the return. But then you also need a system pump and a building loop temp sensor.

Also, did this condition just arise? Or have you been dealing with these lockouts since 2006? It might be that your heat exchanger is calcified and needs a good flush.