Product Information
Description
Harwil MRQ850-9039 Flow Switch for Marquis Spas
Flow monitoring for select Marquis spas.
The Harwil MRQ850-9039 Flow Switch (PST SKU PST-850-9039) is a replacement water-flow switch for the Marquis spa models listed below. It monitors circulation as part of your spa's heater safety circuit. Match your spa's year, model designation, and original part number before ordering.
| Manufacturer | Harwil Corporation |
|---|---|
| Model / MPN | MRQ850-9039 |
| PST SKU | PST-850-9039 |
| Part Type | Spa flow switch |
| Compatible Spa Brand | Marquis |
|---|---|
| Model Years | Select 1994 through 1999 models, see compatibility below |
| Function | Water-flow monitoring for the spa heater safety circuit |
| Manufacturer Warranty | 12 months |
|---|
- 1999: Euphoria MTS, Reward MTS.
- 1998: Reward MTS, Euphoria MTS, Spirit LS.
- 1997: Reward MTS, Euphoria MTS, Quest MTS, Departure RS, Mirage RS, Voyage RS, Destiny CS, Serenity CS, Spirit CS.
- 1996: Euphoria MTS, Quest MTS, Retreat MTS, Reward MTS, Departure RS, Mirage RS, Voyage RS, Destiny 120 Volt, Destiny 240 Volt, Oasis CS, Spirit CS.
- 1995: Euphoria MTS II, Reward MTS II, Mirage MTS I, Quest MTS I, Retreat MTS I, Oasis MTS I, Spirit MTS I.
- 1994: Crossing MTS II, Euphoria MTS II, Reward MTS II, Secret MTS II, Voyage MTS II, Mirage MTS I, Retreat MTS I, Spirit MTS I.
Does this fit every Marquis spa?
No. Use the model-year list above and match your original part number. MTS I, MTS II, MTS, RS, CS, and LS identify different model configurations; a shared spa name alone does not confirm fitment.
Will replacing the switch fix every heating problem?
A flow switch monitors water movement; it does not create circulation. Have a spa technician confirm the switch has failed and check the circulation system before replacing it.
Installation Notice
Have a qualified spa technician install and test this switch. Disconnect power before servicing and never bypass the flow switch, because operating the heater without adequate water flow can damage it.
Additional Info
| Category | Parts Spa Parts Spa Flow Switches |
| SKU | PST-850-9039 |
| MPN | MRQ850-9039 |
| Manufacturer | Harwil Corporation |
| Weight | 1.0 lb |
Let customers speak for us
This costume is legit. It has the sparkle, glittery sheen to it like the one used on screen! Very happy with it!!
Excellent service!
PST was great at communicating the status of my order throughout the various stages. I actually did encounter a shipment issue and they handled it without issue. I will be doing business again with them.
PST was great at communicating the status of my order throughout the various stages. I actually did encounter a shipment issue and they handled it without issue. I will be doing business again with them.
as described, fast shipping
My wife has RA and is always uncomfortable. Our hot tub heater failed and all the local shops were not able to assist until November. I was able to order an exact replacement part which was delivered within 3 days the hot tub was up and functioning in three days. I was very impressed with the quality and service.
Good quality just ordered wrong size and also need thicker cover
Fit perfectly, and fast shipping
Super fast shipping and reliable product !
I accidentally broke the original **** by tightening it too much. This was a perfect fit and works 100%. Fast delivery too!
Swapped out broken heater (lasted about 6 years) for this one. The instructions are for the electronics, not for the plumbing. You must get everything perfectly aligned or the plumbing may leak. I needed to loosen the electronics box to get the plumbing perfectly aligned. I have hot water again.
Great prices, fast shipping, great products
Haven't received yet but I'm sure it'll be great
Ordered on Saturday and we're delivered by Tuesday! Great products and great prices!
PST pool supplies are great to work with. I was having trouble finding this heat exchanger . Everywhere I looked, it was out of stock or back ordered. I contacted the manufacturer about buying the heat exchanger. They told me I couldn't buy it because I wasn't a dealer. If I was a dealer, they would be able to take the order. And make one, it would take 5 to 8 weeks. I contacted PST they put my order in and I received it in about six weeks. Fantastic people to work with. Thanks Tim
