ThermoMate CZ422LP Propane Tankless Water Heater: 113,000 BTU/h

What it delivers

The ThermoMate CZ422LP Propane Tankless Water Heater is a propane tankless with a 113,000 BTU/h burner and a stated maximum flow of 5.0 GPM. Its listing gives a UEF of 0.81.

Flow depends on how cold the incoming water is. Our estimate from its input: 3.9 GPM at a 45°F rise, falling to 2.5 GPM at 70°F, which is 1 shower at 2 GPM on a cold-climate winter day. Size it to your fixtures and climate.

Gas load at full fire: about 1.2 gallons of propane an hour. An older half-inch line that already feeds a furnace often can't spare that, so have a gas fitter check the pipe size and run.

Its exhaust runs hot, so the vent must be the material its manual lists, usually stainless; budget for the vent kit.

Also on the listing: connections: 3/4" npt; material: 5 GPM; model: CZ422LP.

The listing gives dimensions of 13.77 in (W) x 21.65 in (H) and a weight of 22 lb.

Right unit for this house?

Install it when

One shower at a time in cold climates
Propane homes
Replacing a gas tank heater

Look at another unit when

More than 1 winter shower at once
Homes without a gas line

Strengths and trade-offs

Strengths

113,000 BTU/h input
Up to 5.0 GPM
UEF 0.81

Trade-offs

Gas pipe sizing to confirm
Stainless venting costs more
Annual flushing on hard water

Install limits

Figures are the maker's or seller's own. Flow at a rise is our estimate from the input; gas, venting and electrical work needs a licensed professional.

Rated performance

Every figure below comes from the source shown in brackets. Where the maker doesn't state something, we say so instead of estimating.

Model number	CZ422LP	Retailer
Dimensions (seller)	13.77"W x 21.65"H	Retailer
Voltage	120 V AC	Retailer
Max flow (maker)	5 GPM	Retailer
Input (maker)	113,000 BTU/h	Retailer
Product weight	22 lb	Retailer
Material	5 GPM	Retailer
UEF (maker)	0.81	Retailer
Fuel	Propane	Retailer
Connections	3/4" npt	Retailer

Rival units at this flow

GASLAND CS422BLP 113,000 BTU Propane Tankless Water Heater113,000 BTU/h, up to 5.0 GPM.

ThermoMate CZ480LP Propane Tankless Water Heater114,000 BTU/h, up to 5.3 GPM.

MIZUDO FDG-CS120AW-LP 120,000 BTU Propane Tankless Water Heater120,000 BTU/h, up to 5.1 GPM.

More gas tankless water heaters rated for similar demand

Full gas tankless water heaters spec grid · Every ThermoMate unit in the catalog

Final verdict

A practical propane tankless for one shower at a time in cold climates.

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Questions buyers ask

Is the ThermoMate CZ422LP Propane Tankless Water Heater big enough for two showers?

From its 113,000 BTU/h input we estimate about 3.9 GPM at a 45°F rise and 2.5 GPM at a 70°F rise, so 1 two-GPM shower with mild inlet water and 1 in a cold winter. The maker's flow chart for this model is the final word.

What size gas line does the ThermoMate CZ422LP Propane Tankless Water Heater need?

At full fire it uses about 109 cubic feet of natural gas an hour or 1.2 gallons of propane. The pipe size depends on the length of the run and every other gas appliance on it; the maker's manual and a licensed gas fitter decide it.