Product Overview
A In-Line Hydronic Heater Expansion Tank is for residential hydronic heating systems. The purpose of an expansion tank is to take on the expanded fluid in closed-loop heating system and refrigerating systems, s as well as closed hydronic solar systems. It is for non-potable water. The purpose of an expansion tank is to control pressure build-up while improving comfort levels and reducing energy costs.
The ZHT18-30 is appropriately sized for expansion overflow with hydronic heating systems with outputs of as low as 50,000 BTUs up to 150,000 BTUs, depending on the type of hydronic heating system you have. As shown in the chart below, the Zilmet expansion tanks can be used across several different types of closed-loop systems. Please see chart below to be sure you have the right expansion tank for your needs. The ZHT18-30 has a tank volume of 4.8 gallons.
| Type of Hydronic Heat / Radiation | ||||
| Boiler BTU Output | Finned Tube Baseboard and Radiant | Convectors and Unit Heaters | Cast Iron Radiators | Cast Iron Baseboard |
| 25,000 | ZHT8-15 | ZHT8-15 | ZHT8-15 | ZHT8-15 |
| 50,000 | ZHT8-15 | ZHT8-15 | ZHT18-30 | ZHT18-30 |
| 75,000 | ZHT18-30 | ZHT18-30 | ZHT18-30 | ZHT24-60 |
| 100,000 | ZHT18-30 | ZHT18-30 | ZHT24-60 | ZHT24-60 |
| 125,000 | ZHT18-30 | ZHT24-60 | ZHT24-60 | ZHT24-60 |
| 150,000 | ZHT18-30 | ZHT24-60 | ZHT50-90 | ZHT50-90 |
| 175,000 | ZHT24-60 | ZHT24-60 | ZHT50F | ZHT50F |
| 200,000 | ZHT24-60 | ZHT24-60 | ZHT50F | ZHT50F |
| 250,000 | ZHT24-60 | ZHT50-90 | ZHT50F | ZHT80 |
| 300,000 | ZHT50-90 | ZHT50F | ZHT50F | ZHT80 |
| 350,000 | ZHT50F | ZHT50F | ZHT80 | ZHT105 |
| 400,000 | ZHT50F |
ZHT80 |
ZHT80 | ZHT105 |
| 500,000 | ZHT80 | ZHT105 | ZHT105 | ZHT150 |
Typically, as a homeowner, your heater is not something you look at or check on a regular basis. You install it (or have it installed) and forget about it until one cold day you realize you have no heat! Hot water expansion is not something that gets thought about on a daily basis so imagining the damage that can be done is also "out of mind". The purpose of an expansion tank is to act as an overflow for the excess water created by the heated water while maintaining safe expansion pressure. The diaphragm inside the carbon steel tank is constructed of thick, heavy duty synthetic rubber. Each tank has been leak tested and all diaphragms are designed for maximum draw down. The seamless diaphragm never stretches or creases.
A Hydronic Heating Expansion Tank can be added at any time. It does not need to be done when your are replacing an old system. But if you are replacing an older system, you should add a hydronic expansion tank!
Tech Specs
California residents see Prop 65 WARNINGS
WARNING!
Warning: Cancer and Reproductive Harm - www.p65warnings.ca.gov
