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The Rialta furnace is supplied by
Company of Dayton, Tennessee.
The standard Rialta furnace model for the QD and HD is the Suburban NT-20SE which
interestingly enough is only rated at 19,000 BTUH. All other models within the
product line have the two digits to indicate the actual BTUH.
On the FD, the furnace is model DD-17DSIW, ducted. Both require 12V DC power to operate the controls and only burn Propane. There
are no 110V AC power requirements for the furnace, fan, or thermostat controls.
Please note that the controls and fan on the furnace only run
on 12V DC. If you are "dry camped" and allow the furnace to run frequently all
night long, in very cold areas you will likely find your coach auxiliary batteries
almost dead by the morning. You'll notice the furnace fan slowing down and starting
to make unusual noises. Running the engine or generator will quickly recharge
them and no harm is done.
The furnace uses an electric igniter to start the combustion
process and no "pilot light" is used. It also incorporates a "sail switch" which
means the gas is not turned on until the fans blow air into the combustion box
and exhausts any possibility of a previous gas build-up. If you listen closely
when you turn on the furnace you'll first hear the fan operate for a few seconds
and then the ignition of the gas begins. If the fan does not come on to expel
any accumulated gases in the combustion area, then the electric ignition is prevented
Also note the two furnace vents that are required to be in
the exterior skin of the Rialta. One is a "fresh air intake" and the other is
the "exhaust vent". If you live in an area that frequently has "mud wasps" or
other such insects that have a habit of building a nest in little confined areas
such as in these tubes, then you should consider covering these vents with a suitable
metal screen material. Suburban does not recommend covering these vents but you
have to be the judge if the problem warrants such coverings.
If your furnace is blowing nothing but cold air, then it probably
is in lock-out mode or the limit switch has opened and not reset, or the sail-switch
has detected that the fan failed to come on first. Lock-out occurs when a problem
exists during the trial for ignition. Your dealer or a Suburban service center
should be consulted to diagnose this condition.
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|Questions & Answers
If you've got questions about your Suburban
RV furnace, check out this list of questions frequently asked by customers.
Can I repair my furnace myself?
No. Never attempt repairs yourself. The unit must be serviced by a
qualified installer, service agency or gas supplier. Improper installation,
adjustment, alteration, service or maintenance can cause property damage,
personal injury or loss of life.
If I have a product problem, how do I get service?
First, if your RV has its original furnace and is still under the
RV manufacturer's warranty, follow the steps described in your RV owners
manual. Second, contact a conveniently located Suburban Recommended Service
Center. A list of such service centers is located in this section of the
web site. Describe to them the nature of your problem and make an appointment
to have the problem corrected. Third, you and the service center can contact
Suburban's Customer Service Department at P.O. Box 399, Dayton, Tenn.,
37321, or call us at 423-775-2131 if more assistance is needed.
Where can I get parts for my furnace?
Genuine Suburban replacement parts are available from Suburban service
centers. If the service agency does not have the merchandise you need
in stock, they can order for you. If there is no Recommended Service Center
in your area, you may contact any local RV dealer or service agency for
assistance. Suburban sells through most RV wholesalers, so the local agency
should be able to order parts for you through their normal source.
My service company/dealer has generic parts for my furnace that cost
less. Are these parts OK?
Use of generic replacement parts is not recommended or approved by
Suburban. Our first concern is your safety. Second is our concern over
product performance and customer satisfaction. When you install a non-Suburban
part, we can guarantee neither. Be aware that use of non-Suburban parts
will void the warranty and you will assume liability consequences. It
also violates the intent of the UL, CUL, AGA or CGA certifications.
Can I use my furnace while driving?
No. Suburban does not feel this is a safe practice. Some states have
laws forbidding the use of propane while driving. You should be sure all
gas appliances are off and their ignition systems are off while the vehicle
is in motion or being towed.
Is it safe to install a bug screen over my furnace vent?
No. Suburban does not approve - nor do we recommend - using the aftermarket
screens being sold to cover the outside vent cap. This restricts the exhaust
and intake air, resulting in improper burner operation and a potentially
My current furnace needs to be replaced. What BTUH size should I buy
to replace it?
Check your furnace data plate for BTUH input. The replacement should
be the same BTUH size or a close equivalent. Do not oversize your furnace.
Too much heating capacity leads to rapid cycling and reduced comfort levels.
If you do choose a larger BTUH furnace, your installer must make sure
the installation requirements meet or exceed Suburban's installation requirements
for ducting, return air, clearances and gas pipe size.
Is there any preventative maintenance required on furnaces?
Yes. We recommend an annual inspection by a qualified service technician.
Also, you as the owner/user should inspect the furnace monthly during
the heating season for the presence of soot on the vent. Operating the
furnace in this condition could lead to serious property damage, personal
injury or loss of life. If soot is observed on the vent, immediately shut
down the furnace and contact a qualified service agency.
Can I close off a register so more heat goes to another part of the
No, this is not recommended. Doing so will cause improper furnace
operation and possible overheating of the furnace.
What causes the majority of furnace problems?
Conditions that can affect the performance of your furnace can include:
Low gas pressure caused by a number
of factors, including a malfunctioning regulator or low gas levels in
the tank. This can only be tested by a qualified service technician.
Low voltage, which again can only
be checked by a certified service technician.
Inadequate ducting. Have your
dealer make sure the furnace has at least the minimum number of ducts
and required duct area (min. sq. inches), excluding closeable outlets.
Check for proper duct connections at the furnace or collapsed ducts.
Make sure ducts are clean and clear of obstructions, and are as straight
and tight as possible.
Restricted or insufficient air
return: the return air passage should meet the minimum open square inches
as specified for the particular model of furnace installed. It must
not be blocked or restricted. Keep the furnace compartment clean of
any materials that can block the air flow around the furnace.
Unauthorized alterations and improper
Failure to adhere to the preventative
maintenance measures outlined in the users manual.
My furnace runs, but it's just blowing cold air. What's wrong?
Your furnace is in lock-out or the limit switch has opened and not
reset. Lock-out occurs when a problem exists during the trial for ignition.
Your dealer or a Suburban service center should be consulted to diagnose
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wall mounted thermostat is made either by
Robertshaw Controls Company or beginning in the 2003 model year also by
Both types are typical of most inexpensive thermostats used in RVs. Its only function
is to determine the surrounding air temperature and signal the furnace to turn
on or off depending upon your desired temperature selection. In the Rialta, it
operates only on 12V DC and there are no 120V AC wires involved in its operation.
There are two minor problems with the Robertshaw thermostat.
First, the thermometer is not only very difficult to read but is known to be somewhat
inaccurate. There is a thermometer calibration procedure outlined in the "Installation
Instructions" sheet included with the new Rialta papers, but most people end up
moving the selector lever to wherever they "feel" is the most comfortable without
actually looking at the temperature read-out.
The second problem is that the on-off lever located on the
bottom moves very stiffly over its limited total travel of approximately 1/4".
You may think that the furnace is off when it really is not, or vice-versa. The
letters indicating on-off are very hard to read so sometimes you must physically
move the lever to make sure it is in the desired position.
The thermostat does NOT have to be installed perfectly level
and will operate in all positions when wired correctly. The only user service
possible concerns the contacts where the temperature control makes or breaks the
circuit. Robertshaw recommends the use of any unglazed paper sandwiched between
the contacts and moved back and forth to polish the contacts and remove any tarnish
buildup. Most "back-yard" mechanics will use a small piece of fine emery cloth
or even extra-fine sandpaper to clean the contacts.
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