Category: Trailer Mods / Repairs

Introduction

There are significant differences in the way RV systems work in comparison to home systems. My goal with this mod is to move those differences in air and heat closer together. We have totally separate heating and air conditioning systems, the short falls are there is little air movement when the heat is running and Gas furnace, alone, really tends to dry out the air, moreover, neither unit has a particularly accurate thermostat, this mod fixes that.

Changes in the System

Removing the analog thermostat and replacing with a digital is key to the entire operation. We are well aware of our optimal winter and summer temperature preferences and analog is so difficult to set up. Digital tends to be more “set and forget”. We plan to run the fan in the AC system with an electric heat element to warm the air without drying it so much, and whenever the gas furnace does operate we want the AC unit to help distribute the heat (air) more evenly.

Parts Required

Parts in the RV:

1. Coleman 48000 Series (48203) Roof Top AC System (Mechanical Controls)
2. Atwood AFSD12 Furnace
3. Atwood Mechanical Thermostat

Parts necessary to perform Mod:

1. Coleman 9330C755 heat ready control box
2. Coleman 9233A4551 heat kit
3. Coleman 6536A3351 2 Stage Heat Pump Digital Thermostat (12VDC)
4. Altronix Timer Relay (2)
5. 3 General purpose Diodes

We will provide a schematic of our hook ups for this unit below.

The Mechanical controls on both heat an AC systems are to be removed for this mod.

Video Description of Mod Testing

Impressions

This mod operates very well. We, actually, also carried an oil filled space heater along and between the space heater and the heater in the AC we never once had the furnace kick on. This trip we camped out in 20 degree weather in a significant cold snap in north Texas, just before Christmas. We also have very accurate control of the AC and Heat Temps and this all totally worked better than ever before. In this mode of operation, we are completely hooked!!

Realize, however, the AC and Electric heat will only work when connected to 110 V …. heat from the furnace will always work with 12VDC. Boondocking is no problem in the wintertime. For this mod to work, and clearly to have AC, one must use a generator or inverter to create 110V while boondocking.

Support Documents

Schematic 1: This is the hookup details for the parts listed above. This particular schematic will operate the Mach 3 in both AC and heat modes, and will also operate the propane furnace. The Mach 3 fan will not run when the furnace is running in this setup.

Air Conditioning Mod for Mach 3 AC System

Schematic 2: This is the hookup details for the parts listed above. This setup requires 2 additional Timer Relays. This particular schematic will operate the Mach 3 in both AC and heat modes, and will also operate the propane furnace. The Mach 3 fan will continue to run when the furnace is running in this setup.

Coming Soon!!

Adding an RV Dinette Introduction / Description

We do quite a lot of RV living in the winter months. We have a hybrid and in the winter it just isn’t comfy sleeping in a tent. Subsequently, we were looking for a way to have a permanent bed, as well as a table for additional counterspace, work, and eating meals. We came up with, considered heavily, and acted upon a plan for a fairly thin table that takes up about 6 inches of walking space.

Our plan involved buying 2 table legs and a 12 inch plank. We have been using this new table for several days and, for us, it works out perfectly. Our RV has very little counter space, and for cooking, we needed just a bit more. This table is a total score!! For working on the laptop, it also works well.

Below is a video we made for the installation.

Installation Video

 

This is a four part video series on choosing, gathering parts and tools, preparing for and finally installing an electric water heater element.  The only reason it is four parts is to keep each individual video around or below the 10 minute range.

 

Part 1:  Choosing the electric water heater system and gathering the parts and tools to do the job.

Unpacking and unboxing the parts for modding an Atwood Propane Water Heater and fitting it with an Electric Heating Element.

Also description of tools one might need for the job.

Parts:

Diamond Group HR6 Water Heater Parts Kit
Website
Light Switch with or Without Pilot Light
Single Gang Old Work Box or Similar

Tools:

6 Way Screwdriver
Electrical Wire Cutter / Stripper
Razor Knife
Wrenches / Pliers
Drill
Drill Bits 1/4 and 1/2
15/16 Socket
1-1/16 Socket
Ratchet
Extension

Optional:

Spade Lugs (Assorted Types)
Crimping Tool

 

 

Part 2 – Prep Work and Installation of Outside Components

Looking over possible obstacles and planning for drilling the hole for cable entry.  Installing the bushing and heating element.  Making up outside electrical connections.

 

Part 3 – Inside Wiring and Switch Installation

Looking over possible places to get electricity to the heater.  Installing the on/off switch.  Making up inside electrical connections.

 

 

Part 4 – Final Connections and Testing

Making up all of the switch connections, crimping spade lugs, another tool recommendation. Discussion of Stranded as opposed to solid cable and the need for spade lugs.

While I realize that a ratcheting crimper is fairly expensive, in the 30+ years I’ve spent in the electronics industry, I have seen lots of connection breakdowns over time. Especially those subjected to more harsh conditions (like in a trailer or RV). To date, I have never seen a properly crimped connector fail at the crimp …. under a screw terminal, yes …. at the crimp, no.

I highly recommend the Paladin PA1305 or PA8021. I use the 1305 and I have several interchangeable die sets that allow me to crimp all sorts of connectors. One of the best tool investments I ever made. There are several manufacturers, out there that make similar crimpers, I just chose Paladin, when I was shopping, years ago. Greenlee and Ideal are two other manufacturers that come to mind as having very similar crimpers.

http://www.alliedelec.com/paladin-tools-pa1305/70199925/
http://www.greenlee.com/catalog/Wire-Termination/WIRE-CRIMPERS

Funny thing happened the other day.  I was doing some electrical work and popped a GFCI plug.  Didn’t think too much about it, went on about my businness and finished the work.  A couple days later I went into the trailer and …. no lights.  Since I don’t plug in, ever …. this only meant one thing, dead battery.  As I looked into the reasons for a dead battery, I discovered that the Solar Charge controller was no longer functioning.  I have ordered a new one, and it is on its way.  I really need to design in a fail safe that disconnects the solar controller when we are plugged in to 110 at a campground.  It sort of makes sense that there could be a spike on the trailer chassis ground for a split second, if and when a GFCI pops, and if there were a spike …. it could detrimentally effect sensitive electronics.  A possible fix is a surge suppressor on the 12V Charge controller line, or a contactor that disconnects the solar whenever we are using 110V ….. I will be doing more testing and evaluating in the next few days to determine the best course of action.

We are heading out on the road in just a couple weeks, I’ll do something with this problem before we do leave.  This post will be updated in the next few days as I decide what to do and get it done.

2016/12/6 – Received a shipment of new Solar Charge Controller. Everything is working as it should be. Still considering exactly how to create, install the disconnect. I use a fairly inexpensive Charge controller from Eco-Worthy, and it is far less than other similar charge controllers, still …. if I can prevent loss and having to spend 100 dollars every time the GFCI is triggered, why not do that. Still thinking through everything. Answer, soon.