Amtrol Product Page
Amtrol is a manufacturer of expansion tanks and indirect water heaters used with radiant heat and boiler systems.
An expansion tank is used as a safety device to allow for expansion and contraction of water as it heats and cools. When a radiant floor heating system is not operating, the water in the system might be allowed to cool. When a thermostat requires heat for a room then the boiler heats the water to the required temperature.
As with any fluid, the water expands to a greater volume as it heats. The expansion tank absorbs the expansion by using a bladder or balloon filled with air. Otherwise the water pressure could build to a very high level and cause leakage in fittings or other joints.
An indirect water heater is a very well insulated water tank with a heat exchanger inside. This heater is used with another hot water source such as a boiler or a desuperheater to make your domestic hot water. It is important to keep your boiler water separate from water used for cooking and bathing if you use the boiler for heating also.
Why use an expansion tank?
1. To eliminate nuisance leaks and possible dangers associated with expansion of water in a closed system
2. Some local building codes now require expansion tanks on all plumbing systems where check valves are also required.
Why use an indirect water heater?
1. Keeps boiler water separate from cooking and bathing (potable) water.
2. Standby losses are much less than conventional water heaters. Most gas fired water heaters lose about 7 degrees F per hour just standing. A super insulated indirect water heater will lose less than 1 degree F per hour. A conventional water heater might have to fire twice per night to maintain temperature and an indirect probably will not fire at all. Thus an indirect water heater is much more efficient storage for hot water.
3. Produces hot water much faster. A conventional 50 gallon gas hot water heater can only provide about 75 gallons of hot water in the first hour and even less than 75 for every hour after the first. If a shower uses 3 gallons of hot water per minute, a standard heater will provide about 25 minutes of shower and then run out of water. An electric water heater would provide less. An Amtrol indirect water heater, using a small 150,000 BTU/hour boiler, can produce over 200 gallons per hour, every hour, for as long as you need hot water. Even if you have a large family it is possible to never run out of hot water.