Pentair MasterTemp 461021 400K BTU heavy duty ASME natural gas pool heaterPentair MasterTemp Digital IID Heavy Duty ASME Natural Gas Low NOx Heater 400K BTU, 461021 In stock$5,02399
Pentair MasterTemp 461021 400K BTU heavy duty ASME natural gas pool heater
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Pentair MasterTemp Digital IID Heavy Duty ASME Natural Gas Low NOx Heater 400K BTU, 461021

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$5,02399
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Quick overview

  • Read this first ASME MasterTemps no longer include tubes and unions, and they cannot be bought separately. Order only if you are keeping the hookups from a previous Pentair ASME heater.
  • Heavy duty cupro-nickel the HD exchanger is built for low pH, high flow and heavy use, the conditions that wear out a standard exchanger.
  • 400,000 BTU natural gas the 400K natural gas model with a low NOx burner.
  • ASME version for installations that require an ASME stamped heater.
  • Digital IID controls electronic ignition with indicator lights that show what the heater is doing at a glance.
  • Compact and quiet a small footprint and quiet operation that stays out of the way of the pool.
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Product details

The Pentair 461021 is the MasterTemp 400 in its heavy duty ASME form: a 400,000 BTU natural gas pool and spa heater with digital intermittent ignition, a low NOx burner and a cupro-nickel heat exchanger. It is the MasterTemp for installations that call for an ASME stamped heater and for water that is hard on equipment.

Before you order

Pentair no longer supplies tubes and unions with the ASME MasterTemp models, and they are not available to purchase separately. Order this heater only if you are certain you have the hookups that came with your previous Pentair ASME heater.

Heavy duty by design

The HD exchanger uses cupro-nickel tubing that stands up to low pH, high flow and heavy use, the conditions that shorten the life of a standard copper exchanger. The rest of the heater is the MasterTemp you know: as simple to run as a home furnace, with indicator lights that make operation and monitoring obvious, in a compact cabinet that runs quietly enough not to intrude on the pool.

Delivery

This is a freight item and ships on a pallet. Inspect it on arrival and note any damage before signing.

Specifications
Brand Pentair
Manufacturer part number 461021
Model MasterTemp
UPC 788379858278
Type ASME pool and spa heater, heavy duty
Fuel Natural gas
Heat input 400,000 BTU/hr
Heat exchanger Cupronickel, heavy duty
Headers Bronze, ASME
Certification ASME
Ignition Hot surface (HSI), no standing pilot
Electrical 120 or 240 VAC, single phase, 60 Hz; ships with the 240 V plug
Amp draw About 5 A at 120 V, 2.5 A at 240 V; 15 A circuit
Gas connection 3/4 in
Water connections 2 in
Cabinet 21 in long, 23 in wide, 29 in high
Controls Digital, rotating display
Tubes and unions Not included, no longer available separately
Ships Freight

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Questions and answers

What people ask about this product, answered by our pool techs.

What is the MasterTemp 400 HD ASME, 461021?
The heavy duty ASME version of the 400,000 BTU heater: ASME certified, with bronze headers and a cupronickel heat exchanger in place of copper. Whether a pool needs an ASME heater is for the local code and the inspector to say.
Does the MasterTemp 400 HD ASME come in propane?
No. Pentair's manual lists the 400 HD ASME, part number 461021, for natural gas only.
Where is the manual for the MasterTemp 400 HD ASME?
Under Downloads on this page, as the Owners Manual. It is Pentair's MasterTemp Installation and User's Guide, part number 472592, which covers the 175,000 to 400,000 BTU models in natural gas and propane, the HD and ASME versions included.
What connections and power does 461021 need?
2 inch water connections and a 3/4 inch gas connection, on 120 or 240 VAC, single phase, 60 Hz. Pentair's manual gives about 5 A at 120 V and 2.5 A at 240 V, on a 15 A circuit.
Can the MasterTemp 400 HD ASME be installed indoors?
Pentair certifies the ASME MasterTemp for indoor installation with its Direct Air Intake Duct Kit. Outdoors it needs no kit.
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