Steam boiler with boiler feed tank.

Joeyjr

I am installing a Weil Mclain 480 and a hoffman 30 gal boiler feed tank. I can't seem to find any good piping diagrams on how to properly connect the two. Do I need a Hartford Loop still? Or just an equalizer?

KC_Jones

Out of curiosity, how is the current tank piped that you feel something isn’t correct?

EBEBRATT-Ed

@Joeyjr
Pipe the boiler in accordance with Weil McLains instructions as far as the risers, header number of take offs everything stays the same. You need an equalizer, you do not have to use a hartford loop but it will do no harm. If you use a hartford use a close nipple between the tee and the elbow if you don't use a hartford just connect the pump discharge into the boiler return.

Put two check valves in the boiler feed pipe one at the boiler and one at the pump. A ball valve at the boiler is a good idea. The pump discharge should have a balancing valve to adjust the pump flow. Usually these are set to maintain the pump discharge at 20psi.

Steamhead

Do you really need that boiler-feed tank and pump?

Jamie Hall

Steamhead said:

Do you really need that boiler-feed tank and pump?

Good question. Cedric -- a Weil McClain 580 -- doesn't have one and has never shown any signs of needing one. If you don't need one, they're a lot more hassle than they are worth. Also, are you installing this at the water line, for extra water volume, or are you installing it as a boiler feed tank? And, if the latter, how are you controlling the feed pump? Please tell me that you will use the boiler water level for control, and feed makeup water -- if any is needed -- into the feed tank.

Pumpguy

Typically, a boiler feed pump and tank would be needed if the boiler didn't have enough water storage capacity to fill the whole system with steam.

If the boiler ran out of water before condensate returned, you would need to take on make up water, resulting in a starve-then-flood situation.

The boiler feed tank should be sized to provide a certain amount of steaming time before needing to take on make up water. Typical steaming times are 10 to 20 minutes.

I like to recommend positive closing valves on the discharge of boiler feed pumps. This is because when the boiler stops making steam, and the steam in the chest and header condenses, a high induced vacuum will occur. This high induced vacuum will pull all of the water out of the boiler feed tank, flooding the boiler. One or more simple check valves in the boiler feed pump discharge pipe will not solve this problem, but a positive closing valve will.

This valve should be wired to the boiler's low water controls so when the boiler calls for feedwater, the valve will open and the pump will start. When satisfied, the valve closes and the pump shuts off.

Joeyjr

Originally the house had a Burnham PF 506, which was Way oversized. It never had a boiler feed tank due to the size of the boiler. Very long steam mains and a significantly smaller boiler, sized appropriately, would run out of water.

nicholas bonham-carter

Was it really running out of water, or was high pressure pushing water out into the returns?—NBC

Jamie Hall

Joeyjr said:

Originally the house had a Burnham PF 506, which was Way oversized. It never had a boiler feed tank due to the size of the boiler. Very long steam mains and a significantly smaller boiler, sized appropriately, would run out of water.

They would have to be very long steam mains. Keep in mind that evaporation of 1 gallon of water will produce 200 plus cubic feet of steam. A three inch ID pipe has about 0.05 cubic feet per foot -- so evaporating 1 gallon of water will fill somewhere around a mile of pipe.

So... it is far more likely that if there is a problem with running out of water it is either, as @nicholas bonham-carter suggested, excess pressure backing water up into pipes it shouldn't be in -- or just simply slow wet returns.

Check that first.

dopey27177

Condensate pump installation for small heating systems is rare.
To see if you really need one show some pictures of the system and provide the boiler size and model including pictures of the basement piping.

Sometimes some modifications to the steam and return piping the condensate lag can be averted,

Jake

New England SteamWorks

A little tip I learned from Dan: If you go with the feed tank, which you probably don’t need, put a PRV on the domestic water inlet. Lots of places have enough water pressure to leak by and flood the tank otherwise.

steam2pipe

We have a commercial Weil McLain boiler that serves 12 units and the auto feeder (vaiours ones installed by 3 different plumbers) never worked right and caused the boiler to flood or shut down. All were removed and the water is being fed manually to the boiler when the heat shuts off every few days or so. The plumber recommends a Hoffman Boiler Feed Tank and all necessary traps and controls would be included, warranty etc though it is very expensive. The hesitation is that we have very old pipes with lots of black sludge. We need to decide on the tank install soon. What I have read in Heating Help describes issues that arise with the tank and pump. Please let me know what you recommend so we can make a good decision. Thanks.