Coleman | Heat Strip | 38203-4551 | For Coleman Mach AC

Add supplemental electric heat to your Coleman Mach RV air conditioner with the Coleman Mach 38203-4551 Electric Heat Strip Kit. This 5,600 BTU heat strip installs into any compatible "Heat Ready" Coleman Mach ceiling assembly — delivering quick electric warmth to take the chill off cool mornings and evenings without firing up the propane furnace. The right add-on for shoulder-season comfort when running on shore power.

5,600 BTU / 1,600W of Supplemental Electric Heat

The 38203-4551 uses electric resistance heating to warm air as it passes through the AC unit's air handler, delivering:

• 5,600 BTU/hr of heat output
• 1,600 watts on 120 VAC shore power
• 15–16 amps draw in operation

Real-world result: chilly evenings get warm quickly without the noise, hassle, or propane consumption of running the furnace.

⚠️ Compatibility — Coleman Mach AC Series Starting with "3"

The 38203-4551 is compatible with Coleman Mach AC and heat pump units in these series:

• 38XXX / 48XXX — Medium Profile (Standard Height)
• 35XXX / 45XXX — Low Profile / Mid Height / Mach 10

This includes the Roughneck and other Mach series units in those profile categories. For modern R-32 generation units, look for AC model numbers starting with "3" (the current generation prefix).

⚠️ NOT Compatible With Mach 8 (47XXX Ultra-Low Profile)

The 38203-4551 does NOT fit Mach 8 (47XXX ultra-low profile) air conditioners or heat pumps. Those units require a different heat strip:

• For 47XXX Mach 8 units: Use the Coleman Mach 47233-4551 Electric Heat Kit instead — a different heat strip designed for the Mach 8's ultra-low profile housing

The two heat strips are NOT interchangeable. Verify your AC model number before ordering.

"Heat Ready" Ceiling Assembly Required

The heat strip installs into the dedicated heater bay of a "Heat Ready" Coleman Mach ceiling assembly and connects to the ceiling assembly wirebox via a 2-pin receptacle. The ceiling assembly must already support a heat strip — cool-only assemblies are not compatible.

Compatible Heat Ready ceiling assemblies we carry:

• Coleman Mach 8430A635 ChillGrille Heat-Ready Lateral Ducted — for lateral-ducted installations
• Coleman Mach 9430-725 Bluetooth Heat-Ready Non-Ducted — for non-ducted Bluetooth-controlled installations

Required Control Box — Heat-Capable Only

The ceiling assembly's control box must also support a heat circuit. Compatible control boxes:

• Coleman 9330C755 Heat-Ready Control Box — for cool-only AC with electric heat strip support
• Coleman 9530A751 Heat Pump Control Box — for heat pump systems

⚠️ Cool-only control boxes (such as the 8330-752) do NOT support a heat strip and are not compatible with this kit. If you currently have a cool-only setup and want to add a heat strip, you'll need to upgrade to one of the heat-capable control boxes above as well.

Dual Part Numbers — Same Kit

This heat strip is sometimes listed under cross-referenced part number 9233A4551. Both 38203-4551 and 9233A4551 refer to the same kit — either part number may appear depending on the supplier or catalog. If you're cross-referencing from a different listing or manual that shows 9233A4551, this 38203-4551 listing is the matching product.

⚠️ Supplemental Heating Only

The 38203-4551 is a supplemental electric heat source — not a replacement for a propane or gas furnace. A few important real-world expectations:

• Best suited to mild temperature conditions — taking the chill off cool mornings/evenings
• Effectiveness decreases as outdoor temperatures drop below 40°F
• For sustained cold-weather heating, the RV's furnace should remain the primary heat source
• Requires shore power — 15-16 amp draw is substantial, so not practical on most generators

Practical Benefits Over Running the Furnace

For appropriate use cases, the 38203-4551 has real advantages over firing up the propane furnace:

• No propane consumption — keeps propane reserves for harder cold-weather demand
• Quieter operation than the furnace burner cycling
• Faster warmup — electric heat is immediate rather than waiting for furnace cycle
• Uses your existing ceiling air distribution

Key Features

• 5,600 BTU / 1,600W electric heat strip for Coleman Mach AC units
• 120 VAC shore power operation — 15–16 amps draw
• Installs into Heat Ready ceiling assembly's heater bay
• 2-pin receptacle connection to the ceiling assembly wirebox
• Easy integration — no extensive AC unit modifications
• For 38XXX/48XXX (Medium Profile) and 35XXX/45XXX (Low Profile/Mach 10) Coleman Mach AC units (model numbers starting with "3" for current generation)
• NOT compatible with Mach 8 (47XXX) — use 47233-4551 for Mach 8 units
• Cross-referenced as 9233A4551 — same kit, alternate part number
• Requires a Heat Ready ceiling assembly with heat-capable control box (9330C755 or 9530A751)
• Compact 2.4-lb kit
• 1-year manufacturer parts warranty (upgradable to 2-year when purchased with a Coleman Mach AC)

Specifications

• Brand: Coleman Mach (Airxcel)
• Part Number: 38203-4551 (also cross-referenced as 9233A4551)
• Type: Electric Heat Strip Kit for Heat Ready Ceiling Assemblies
• Heat Output: 5,600 BTU/hr
• Wattage: 1,600W
• Voltage: 120 VAC
• Amperage: 15–16 amps
• Compatible AC Series: 38XXX/48XXX (Medium Profile) and 35XXX/45XXX (Low Profile/Mach 10) Coleman Mach AC and heat pumps
• Required Ceiling Assembly: "Heat Ready" Coleman Mach ceiling assembly
• Required Control Box: Heat-capable (9330C755 or 9530A751) — not cool-only (8330-752)
• Connection: 2-pin heater wire receptacle to ceiling assembly wirebox
• NOT Compatible With: 47XXX Series (Mach 8 / Ultra-Low Profile) — use 47233-4551 instead
• Use Type: Supplemental heating only (not a furnace replacement)
• Optimal Ambient Range: Above 40°F
• Weight: 2.4 lbs
• Warranty: 1-year parts only manufacturer warranty (upgradable to 2-year when purchased with a Coleman Mach AC)