Community Forums

patrickemb · 03-22-2018, 07:35 PM

Yes, where was this answer a page ago! Lol 😂

Stealth01 · 03-23-2018, 06:04 AM

Quote:

Originally Posted by patrickemb

Yes, where was this answer a page ago! Lol 😂

Because I'm a retired Aerospace Engineer... I like to provide detailed answers, so you'll know the "what" with the "why"!

barnegatepic · 03-23-2018, 12:12 PM

Quote:

Originally Posted by Dutch Star Don

"patrickemb"....Yes to your above statement. Think of it this way. The summer loop or as it should be called hot water loop, as stated above, is ONLY supplying hot water to the sinks and shower. It's heating the water in the Oasis tank/burner and pumping it to the sinks and shower.

When you turn your thermostat to furnace, the Oasis unit is now pumping BURNER FLUID, not water, to all of your registers throughout the coach. So when the furnace comes on, the burner fluid is being heated and passed through those registers. The fans come on and you get heat.

During the summer, if the thermostat is set to furnace, even though it may be set well below the inside temperature, the Oasis unit is still pumping burner fluid through those hoses to the registers and back. It does this in anticipation of you turning up the thermostat and demanding heat. You would be amazed how much heat the registers and hoses produce, even while sitting at idle. Enough heat to raise the inside temperature of the coach, even on a warm day.

On our first trip with the new coach, the weather was warm during the day and cool at night. We would set the thermostat down during the day, but the coach was way to warm. We soon learned about turning the furnace off when not in use.

Don I thought the same thing on our 2017 until I saw a post that there was a faulty check valve which caused it to generate heat when just hot water was needed. I don't think the heat exchanger should be heating in hot water only mode so to speak. Just a thought.

Algoma · 03-23-2018, 12:17 PM

Quote:

Originally Posted by barnegatepic

Don I thought the same thing on our 2017 until I saw a post that there was a faulty check valve which caused it to generate heat when just hot water was needed. I don't think the heat exchanger should be heating in hot water only mode so to speak. Just a thought.

You are correct. There should be no heat in the heating loops inside the coach if the "summer loop" alone is on.

99phantoms · 03-23-2018, 01:43 PM

Good discussion... 2 clarifications please -

There are 2 Oasis zones for hvac heating... usually front (zone 1) and rear (zone 2)?

In the situation where either zone furnace is selected ON, BUT the requested temp for that zone is set below the ambient temp in that zone (ie, no heat called for at the moment), then there IS or there IS NOT boiler fluid flowing thru all the registers in that zone. (I understand the individual register fans will be OFF until heat is called for, and the boiler fluid at the register is at a minimum temp) And do the 2 zones operate independently of each other based on whether or not each zone's furnace is turned on or off at the thermostat?

Stealth01 · 03-23-2018, 03:06 PM

Quote:

Originally Posted by 99phantoms

Good discussion... 2 clarifications please -

There are 2 Oasis zones for hvac heating... usually front (zone 1) and rear (zone 2)?

In the situation where either zone furnace is selected ON, BUT the requested temp for that zone is set below the ambient temp in that zone (ie, no heat called for at the moment), then there IS or there IS NOT boiler fluid flowing thru all the registers in that zone. (I understand the individual register fans will be OFF until heat is called for, and the boiler fluid at the register is at a minimum temp) And do the 2 zones operate independently of each other based on whether or not each zone's furnace is turned on or off at the thermostat?

Yes, Zone 1 is forward and Zone 2 is aft. With either Zone furnace (heat) turned on BUT the zone thermostat setting is below ambient there will be NO boiler fluid flowing through any heat exchanger! The Zone 1 or 2 loop pumps turn on when zone heat is called for; the pumps turn on and the heat exchanger fans turn on. Yes, the two zones operate independently of one another. Zone 1 Loop Pump does not provide boiler fluid flow in Zone 2 nor does Zone 2 Loop Pump provide fluid flow in Loop 1.

Algoma · 03-23-2018, 03:48 PM

Quote:

Originally Posted by Stealth01

Yes, Zone 1 is forward and Zone 2 is aft. With either Zone furnace (heat) turned on BUT the zone thermostat setting is below ambient there will be NO boiler fluid flowing through any heat exchanger! The Zone 1 or 2 loop pumps turn on when zone heat is called for; the pumps turn on and the heat exchanger fans turn on. Yes, the two zones operate independently of one another. Zone 1 Loop Pump does not provide boiler fluid flow in Zone 2 nor does Zone 2 Loop Pump provide fluid flow in Loop 1.

That is absolutely correct. But just to clarify (or muddy the water) Oasis uses the term "loop" but the Dometic thermostat uses the term "zone". If you have 3 a/c units you have 3 "zones" but the Oasis only has 2 "loops". So Zone 1 (front of coach) is loop 1 and Zone 3 (rear of coach) is loop 2. Zone 2 (center of coach) does not have any Oasis function.

Dutch Star Don · 03-23-2018, 05:11 PM

I don't think I said anywhere that there was heat in the heating loops if only the summer loop is on!

99phantoms · 03-23-2018, 06:40 PM

This is where I got conflicted.

Quote:

Originally Posted by Dutch Star Don

During the summer, if the thermostat is set to furnace, even though it may be set well below the inside temperature, the Oasis unit is still pumping burner fluid through those hoses to the registers and back. It does this in anticipation of you turning up the thermostat and demanding heat. You would be amazed how much heat the registers and hoses produce, even while sitting at idle. Enough heat to raise the inside temperature of the coach, even on a warm day.

Quote:

Originally Posted by Stealth01

With either Zone furnace (heat) turned on BUT the zone thermostat setting is below ambient there will be NO boiler fluid flowing through any heat exchanger! The Zone 1 or 2 loop pumps turn on when zone heat is called for; the pumps turn on and the heat exchanger fans turn on.

Stealth01 · 03-24-2018, 06:09 AM

99Phantoms,
Loop pumps turn on when heat is "CALLED FOR", that is when "heat" is on and the ambient temperature is below the thermostat setting. The Loop Pump turns on as well as the heat exchanger fans. If you doubt it, pull your DM12 Distribution Module cover off and look for yourself.

Algoma · 03-24-2018, 06:24 AM

Quote:

Originally Posted by Stealth01

99Phantoms,
Loop pumps turn on when heat is "CALLED FOR", that is when "heat" is on and the ambient temperature is below the thermostat setting. The Loop Pump turns on as well as the heat exchanger fans. If you doubt it, pull your DM12 Distribution Module cover off and look for yourself.

Just to confirm this I checked my coach which is behind my house. The Zone 1 and 3 thermostats are set at 50 and the inside temperature is currently 51. The loop pumps are not running and the hoses are cool. I am using AC1&2 but not the diesel burner.

Tizbad · 03-24-2018, 09:59 AM

Our previous motorhome had an Aquahot system. During the summer, I'd ocassionally "call for heat" to cycle the pumps for a couple of minutes. I recall reading that this was a good practice so that the pumps don't get stuck due to non-use in the summer. We never had any problems with it and it as 11 years old.
Is this true with Oasis pumps too?

Dutch Star Don · 03-24-2018, 10:45 AM

I guess mine has been broken for four years. It stills heats the coach through the floor.

joes2901 · 03-24-2018, 01:12 PM

I spend the summers (4 to 5 months) in high altitude (7,000 +/- 1000 feet) Rocky Mtn campsites without any hookups or outside AC power, I want hot water but do not want even 1 BTU of heat to come from the Oasis hoses or heaters into the coach. Will the Oasis diesel burner keep the hot water hot, or is there a long delay for the 60 degree water in the holding tank to be warmed to 125 at the faucets?

Does the Oasis heat the Ventana's holding tanks in sub-freezing weather or are the heat pads still needed?