seized circulator pump?

Someone commented in another thread that using your oil-fired baseboard heat occasionally would help prevent the circulator pump from seizing from disuse. Since I started burning coal, only the domestic hot water circuit of my oil boiler is used regularly. Should I be worried about the other pumps?

While we are on the subject, can you plumbers tell me why my oil system has three circulators for its three circuits? Why not one circulator pump, and three solenoid valves to open and close the three individual circuits? Wouldn't that be cheaper and simpler?

I occasionally turn my oil-heat on to make sure everything is in good working order, my upstairs zone only get turned on a few times per season and I've never had a problem with anything seizing up.

As for your plumbing question, a lot of homes use a setup like you described, with one circulator and zone isolation valves for each separate heating zone. It is a cheaper way to do it compared to separate circulators on each zone, but there is no advantage other than cost. The downside is that the circulator on a system with zone valves is usually over or undersized depending on the heat load.

i.e. The flowrate through each zone will change depending on if another zone valve is open at the same time.

Depending on your boiler water quality the water lubricated cartridge pumps can have a problem starting after a long period of non-use. It's because permanent split phase motors, which is what these motors are, have very little starting torque. One example Taco 007. The variable speed motors of this style, that use electronics to vary the speed, also will periodically power on the motor independent of thermostat demand. This lubricates the ceramic internal bearing. That's why you should leave boilers with these types of circulators powered during the summer.

My comments above do not apply to circulators that have external motors, i.e. an inline coupling to the pump. Their motors have much more starting torque.

Why multiple pumps? Pick a reason. The price of a cartridge circulator is similar to that of a zone valve. Often the circulator is more reliable than the zone valve. Using a single circulator with multiple zones would usually require a larger circulator. The multiple circulator system is easier to design, if it was designed at all. Many just install multiple circulators because they know it will work.

I wouldn't worry about pumps seizing. It's rare, and it they do a rap with a hammer wakes them up.

Every plumber has his prefered method and your question has been asked 1,000 times and talked about since the invention of zone valves. Obviously before zone valves got perfected a seperate pump for each zone was the only way. When zone valves first came out the idea was to not only save money on parts, but to save money on electricity. There were lot's of problems though and many plumbers decided "I'll never install another one of those stupid things". But, time marches forward and zone valves are very dependable. They're NOT cheaper than a pump A 007 is about $75 and most zone valves are $85 or more. A zone valve doesn't need a flow check though so you save some there. It does take less labor to install a zone valve, but not much. Most systems could have either, but sometimes you get long runs, radaitors, infloor radiant, and one pump just won't do the job. My house has three pumps and five zone valves. A bit over board for a ranch, but we have good control!

Thanks for the replies. All the zones get used at least a few times a year, so I will just not worry about pumps seizing. And I do have hammers on hand in case Freddy's remedy is needed.

Just make sure you rap the pump casing with the hammer and not the motor.

I would think the number 1 reason for multiple pumps is if you have one and it fails you are done heating your home until it is fixed. Three pumps gives you a considerable backup.

I think the reason is for simplicity, having 3 pumps for 3 zones really makes installation easy for people like me who don't trust zone valves.

With 3 circulators, if one stops, you can always use the others for heat. You'll also probably need R845A relays for the other two circulators.

I have a single Taco 007 with shut-off flanges on both sides, making a replacement a 10 minute job and without having to bleed the system. It easily moves the water for 3 zone valves and loops.

Take your pick. It's more of a personal preference.

The Taco 007 series pumps seize at the rotor shaft to ceramic bearing interface. It's a water lubricated design which depends on continuous rotation or at least semi-regular rotation. The variable speed Taco designs which are base on the same mechanical parts include a feature that automatically turns on the motor. For the 007 variable speed, "Pump Exercise (10 Seconds After 3 Days of No Operation)". There is no way hammering the exterior of the the pump would un-seize a Taco 007. The pump rotor and impeller is integral replaceable cartridge. The mechanical path for any exterior hammer shock to the rotor shaft is nil. The wholesale price for a replacement cartridge is $35-50 depending on who you are and the quantity purchased.

I like the "Pump Exercise". They're thinking all the time!

Another reason for zone valves is power savings. One pump and 5 Honeywell zone valves draw about 125 watts. 5 pumps will draw about 450.