Dometic KRA Series User Manual

Dometic KRA Series

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COPYRIGHT © 2006-2018 Dometic Corporation. All Rights Reserved.

No part of this publication may be reproduced, translated, stored in a retrieval system, or transmitted in any form or by any means

electronic, mechanical, photocopying, recording or otherwise without prior written consent by Dometic Corporation. Every precaution

has been taken in the preparation of this manual to ensure its accuracy. However, Dometic assumes no responsibility for errors and

omission. Neither is any liability assumed for damages resulting from the use of this product and information contained herein.

KRA Refrigeration Systems

(with R-404A refrigerant)

Installation, Operation & Maintenance Manual

KRA 433X

Air-and-Water-Cooled

KRA 450X

Air-and-Water-Cooled

Dometic Marine

Rev. 20180906

L-3571 English

P/N: 340161

KRA 433X

Water-Cooled-Only

Table of Contents

Questions and Answers:

J
jasonsteeleAug 16, 2025
Why is my Dometic KRA running but not cooling?
- B
  Bethany HuffmanAug 16, 2025
  If your Dometic Marine Equipment's compressor and fan (or pump) are running, but the box isn't cooling, it could be due to several reasons. First, check the fan and coil for proper airflow and ensure adequate ventilation, especially if the temperature exceeds 100°F/38°C. Also, inspect the seawater system for proper flow. Other potential causes include an incorrectly set Thermostatic Expansion Valve (TXV), which requires a technician's attention, or a low refrigerant charge, which necessitates checking for leaks and recharging the system with R-404A. A mechanical failure of the TXV could also be the culprit, requiring diagnosis and replacement by a technician.
J
Joseph LyonsAug 19, 2025
How to troubleshoot a Dometic KRA when compressor and fan do not run?
- T
  thomasrhondaAug 19, 2025
  If the compressor and fan (or pump) of your Dometic Marine Equipment do not run, start by checking if the circuit breaker is off and turn it on or reset it if necessary. Then, check the thermostat and ensure it is set for a cooler setting. Also, the issue might be related to a High/Low pressure switch; in this case, check the Dometic control for fault codes LP or 1A and consider calling a technician.
K
kriosAug 23, 2025
What to do if Dometic KRA Marine Equipment fan runs but compressor doesn't?
- B
  brandonbrennanAug 23, 2025
  If your Dometic Marine Equipment fan or pump operates, but the compressor doesn't (and the high-pressure switch or thermal overload has tripped), check for low voltage to the unit, as the Klixon may be open. Also, check the fan and coil for proper airflow to ensure adequate condenser cooling. If the temperature is above 100°F/38°C, ventilate the area. Inspect the seawater system as well. The problem might be related to a High/Low pressure switch, requiring you to check the Dometic control for fault codes LP or 1A and consult a technician.
E
Emily MontgomeryAug 27, 2025
How to fix Dometic Marine Equipment with unlit displays?
- R
  Richard YoungAug 27, 2025
  If the displays on your Dometic Marine Equipment are not lit, check the circuit breaker first to ensure that power is connected. Then, inspect all connections for any looseness. Also, verify that the voltage input of the control is correct. If these steps do not resolve the issue, consult a technician.
C
chavezalexandriaAug 31, 2025
Why does my Dometic KRA Marine Equipment freeze and stop cooling?
- R
  robertedwardsAug 31, 2025
  If your Dometic Marine Equipment system starts to cool, but stops as plates freeze, check the sight glass for moisture. Yellow indicates moisture; green indicates a dry system.
M
Megan BoothSep 3, 2025
How to improve cooling of Dometic KRA Marine Equipment box?
- N
  Nicole SanfordSep 4, 2025
  If your Dometic Marine Equipment is not cooling the box sufficiently, turn the unit OFF and defrost it according to the instructions in 'Defrosting'. Ensure that the thermostat is properly set. Minimize the amount of time the box is open to prevent warm air from entering. If you've recently added many warm items, allow the unit time to cool them. Replace any poor seals and ensure there's a drain plug. Other potential issues include an improperly set Thermostatic Expansion Valve (TXV), low refrigerant charge, high condensing temperature (introduce cooler air into the compartment), improperly mounted temperature sensor, moisture in the system, or inadequate design.
V
Virginia MasonSep 7, 2025
What causes Dometic KRA compressor to run but seawater pump to fail?
- C
  Carrie CraigSep 8, 2025
  If the compressor operates, but the seawater pump doesn’t for your Dometic Marine Equipment, turn on or reset the pump breaker. Check the pump relay and pump relay trigger.

Dometic KRA Series Specifications

General

Type	Refrigerator
Series	KRA
Voltage	12V/24V DC
Capacity	Varies by model (refer to specific model specifications)
Energy Consumption	Varies by model and usage conditions
Refrigerant	R134a
Weight	Varies by model (refer to specific model specifications)
Dimensions (H x W x D)	Varies by model (refer to specific model specifications)
Installation	Built-in

Summary

SAFETY INSTRUCTIONS

General Safety Guidelines

Provides essential safety rules for installation, operation, and maintenance.

Refrigerant Handling Safety

Details safety precautions for handling R-404A refrigerant.

SYSTEM INSTALLATION PROCEDURES

Electrical Safety and Tools

Highlights electrical safety precautions and lists necessary installation tools.

INSTALLATION GUIDELINES

Condensing Unit Placement and Operation

Details the placement and operating conditions for the condensing unit.

Evaporator and TXV Installation

Refrigerant Charge Information

Discusses refrigerant charge, system sensitivity, and repair procedures.

REFRIGERATION SYSTEM OPERATION

Pre-Start-Up Checklist

Provides a comprehensive checklist before starting the refrigeration system.

System Start-Up Procedure

Outlines the step-by-step procedure for starting the refrigeration system.

Multi-Evaporator System Checks

Dometic Control Operation

SERVICING YOUR REFRIGERATION SYSTEM

Refrigerant and Charging

Discusses R-404A refrigerant, charging, evacuation, and system shutdown.

SERVICING AND USER MAINTENANCE

TXV Adjustment and Service

TROUBLESHOOTING GUIDE

Common Problem Diagnosis

Cooling and Freezing Issues

Thermostat Error Code Reference

FIGURES AND DIAGRAMS

KRA 433X 2-Box Installation Diagram

Detailed installation diagram for a KRA 433X system with two fish boxes.

KRA 450X 3-Box Installation Diagram

Detailed installation diagram for a KRA 450X system with three fish boxes.

Refrigerant Pressure-Temperature Chart

KRA 433X 1-Box Wiring Diagram

Illustrates the wiring schematic for a KRA 433X unit connected to one box.

KRA 433X 2-Box Wiring Diagram

Shows the wiring schematic for a KRA 433X unit connected to two boxes.

KRA 450X 1-Box Wiring Diagram

Illustrates the wiring schematic for a KRA 450X unit connected to one box.

KRA 450X 3-Box Wiring Diagram

Shows the wiring schematic for a KRA 450X unit connected to three boxes.

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