What is a Combi Boiler? Compact Mechanicals with Wade Paquin!

[@richarddicktaylor219]

Combi gas boilers will only be legal in UK new builds until 2025 but will be allowed (for now) in remodels after that. The outside device you refer to is known as Weather Compensation, which is popular in Europe but often needs some tuning to work well and few UK plumbers are trained to install it correctly.

[@rs2024-s4u]

Incredible to vent a gas heater 200k BTU with 2" PVC, first Rinnai I used was my home in 1979 renovation at Miami Beach 100K BTU gas vented Rinnai tankless waterheater with galvanized double wall 5" vent stack never had any issues and is still being used today 44 years after install by current owners stainless steel fireboxes last. Ray Stormont

[@pierredelecto7069]

Yup. Something about mounting these things to a sheet of plywood and venting through plastic makes me uncomfortable. I'd prefer it bolted directly to the block and vented through metal.

[@publicmail2]

Still using a Seisco 18kw electric tankless 25 years old. Now out of business bought by AO smith. All Dupont high temp plastic chambers with 4x4500 watt standard elements still original, no moving parts, auto grade temp sensors, and stable temp regulation. Paid $600 new.

[@The518sean]

Love my combi boiler. Super efficient, space savings and energy saving

[@mrstinky2421]

Vs the alternatives it is far from efficient

[@matt45540]

I don't like you quoting a 30 plus year duty cycle on this. It's a sponsored ad tell me what their warranty is

[@157-40_T]

I like it for a small cabin application. The cabin will have a fireplace but the combi could keep it at 50 or so while unattended. And have hot water for showers & dishes.

[@eddtheduck]

Here in the UK 🇬🇧 we have been using combi boilers for years they are great

[@TENTHIRTYONE]

That gray pipe is CPVC (assuming it’s not System 636 as that would be really nice and something to call out as built well) and it is NOT “cheap”. Don’t gloss over using that stuff for exhaust - a lot of guys want to use normal PVC. It’s not the same.

[@patrickcorcoran4377]

Code dictates it in a lot of markets. Most of the Northeast is already mandating CPVC/Polypropylene for flue piping, or headed that way.

[@Eric998765]

Even better, look up monobloc air-to-water heat pumps. One unit can do DHW, radiant floor, forced air heat, and forced air cooling. They aren't cheap ($8000 + for the unit alone) but extremely energy efficient and one unit to do it all is major convenience factor

[@FunwithBooboo]

We have the Rinnai Combi boiler installed in our recently finished IFC house. It's the bomb.

[@AnotherMe890]

I'm using the same thing in the ICF home I'm building right now.

[@flyingmachineworks]

What you save in efficiency you spend in retrofit installs and maintenance.

[@ryansoo4000]

Wade Paquin is a living god!

[@D2O2]

"Tay-co" 😂 Tay-co Tuesday

[@patrickcorcoran4377]

That's how it's pronounced! TACO is derived from "Thermal Appliance Company"

[@sethborman7844]

In a low load house this can be done with a heat pump water heater, as well.

[@jerseygryphon]

It's a pity that you can't combo a heat pump unit with a water tank easily so that the heat removed by the AC heats the water.

[@Aethid]

A heat pump can handle any sized property. Just like with gas boilers, you need to install a unit with appropriate power output for the property. The only special requirement for a heat pump over a combi boiler is that the heat pump will have a lower flow temperature at a higher flow rate for the same given BTU/kW. This means a heat pump needs larger radiators. Underfloor heating is ideal. The size or heat load of the building is not something either technology is more or less suited to.

[@sethborman7844]

@@jerseygryphon you can, it's called a desuperheater.

[@sethborman7844]

@@Aethid read it again. I said "water heater." Of course a heat pump can do anything, but then you also need a water heater (or a system that does both, which is rare).

[@Aethid]

@@sethborman7844 Heat pumps are *usually* water heaters. The most common kind of heat pump is an air to water heater which can function as a drop in replacement for either a combination or system boiler.

[@robertamadiz2692]

Great Video! Thank you for sharing. Considering getting one, does it work on propane gas?

[@annarboriter]

I must be missing something. The heating system is forced air off of hot water manifolds? What advantages does this apparent complexity have over subfloor heating or radiant heaters? I have never liked forced air so I am quite confused by what is going in with this rehab

[@Phil-D83]

My next hvac upgrade

[@alberthartl8885]

Have installed both Navien and Noritz combi boilers for my customers. Matched them up with Uponor controls and manifold. Highest gas bill last winter was $47 for one month. Have never used Rennai tankless units. With 40 years as a general contractor, I was never impressed with how they were made.

[@jonbradshaw3385]

What does something like this cost? Since I am aware most companies won’t give an exact price for a particular unit, it would certainly be nice to know what this unit/system cost in the house in this video and when it was filmed.

[@dukebeach1]

I just got a quote for a boiler only unit, 200K btu, 4,000 sq ft house $22K for unit and install on an existing hydronic floor system. I’m sure this is more. This is why they are not common.

[@Leo-wd8vq]

Convert old oil boiler to gas based heating and hot water combi without tank. Get quote, New York, 30k. Equipment cost is not main driver here.150 or 200 BTU may be only $1000 diff.

[@VictorNolochemical]

Great share, ty 🙏

[@duanehundley]

What is the maintenance like?

[@BOHICA_]

@2:40 - He says "hot water heater". I thought that was a southern thing to say.

[@Wideout4]

My sister has this installed in her 3 unti building and she complains that though kitchen sink receives proper hot water the bathtubs do not warm at best. Recent renovations added a second tub to one of her bathrooms any idea why that is happening

[@johnfitzpatrick2469]

That is very fine copper plumbing. 🌏🇭🇲

[@adriancarey7848]

Millions fitted in Europe, a bizarre and unusual device in US.

[@kevinhornbuckle]

Could this unit supply domestic hot water and also heat a hot tub?

[@alberthartl8885]

Sure

[@chrissaucier121]

Good video…been looking to ditch an old oil boiler (live in Maine). However, I’ve always a bit skeptical when these videos are sponsored by the manufacturer

[@mrstinky2421]

As you should be. I would near install this system myself.

[@patrickcorcoran4377]

Plenty of this exact type of system in Maine, they work fantastically!

[@georgechin7932]

Does it require maintainance annually? How much maintenance costs per year?

[@tachikaze222]

wow, with PG&E natgas costing ~0.10c/kWh this is price-competitive with heat pumps! My tank natgas water heater is in a closet in my garage and I can see putting this in instead, for baseboard heating in combination with an attic heat pump / A/C system.

[@xoxo2008oxox]

I've a similar old home and went with a WeilMclain 97+ combo. I can't find a plumber now, with experience, on the hotwater side since the installers are no longer in business and it needs a flushing (reserve tank). Hydronic end is maintained but again, those are HVAC guys, not interesting in plumbing aspect. Matt- I didn't know the condensate was acidic. Could that explain losing the pump hose barb every few years like it melted? Could you explain more detail on the exit condensate treatment?

[@jonh1808]

Condensate pipework must be either plastic or stainless. Anything else metallic will rot in no time. Condensate from boilers is mildly acidic. It’s why the flue is PVC. If you have a condensate leak within the boiler and you don’t realise, you’ll be surprised how much of a mess it will leave. Be careful where you terminate the condensate pipe. It should go into a foul water pipe, not rainwater. During times of the year when there isn’t much rain it won’t get washed away and can lead to damaged drainpipes. If you have no alternative but to terminate in a rainwater pipe, fit an inline neutraliser.

[@Colinfichman]

Matt has a Rheem heat pump in his house for a reason.

[@D2O2]

They have it to him, that's the reason.

[@joemully6666]

Can you use alternative fuel for those combi boilers, like electric or oil or propane? Or are they natural gas only?

[@jonh1808]

Natural gas or LPG. You get the changeover kit as standard, it’s not a big deal, mainly changing the injectors for ones with a smaller hole (LPG runs at higher pressure), then commissioning the appliance accordingly. You don’t get oil versions. You do get instantaneous electric water heaters, just depends how enormous you want your electricity bill to be. More often than not you’d be as well with a modern stainless high recovery tank using an immersion heater, not cheap to run but very cheap to maintain. Combi boilers on the other hand, very efficient but expensive to maintain in the long run, over its lifespan you’ll replace every single part twice. Worth thinking about if you’re looking at long term cost, especially if you don’t have a huge demand for hot water and can happily live with a smaller tank. Modern cylinders are very well insulated and don’t have much of a heat loss over the day, and are also high recovery, they’ll heat back up quickly.

[@snowgorilla9789]

Do they come in propane version?

[@bigcrisbie7244]

Propane conversion kit is included in the box

[@snowgorilla9789]

@@bigcrisbie7244 thanks, this system would be a great option for a fixxer upper that only had electric heat (baseboard) and maybe no natural gas. Am looking for the retirement place away from the city and the more options to improve the better !

[@markhoffman]

Combi boiler kept my house a toasty 22-24c warm in -25c winter and provided all hot water needs for only $47 in gas usage cost. Good luck competing with that heat pump zealots!

[@OGCJ10]

Which one did you get ?

[@JG-iq2qv]

I wish my furnace was as efficient as my rinnai.

[@MT-me4ny]

SAFETY GLASSES?

[@baxt1412]

Safety sally alert

[@c.n.297]

Hey Matt, could this unit work as a standalone solution for heating and cooling or just heating?

[@fuzzy3440]

When they're talking about the system Matt mentions that there is a Unico small duct high velocity ac/heater system. That combi boiler provides heat to the Unico.

[@tysleight]

Having 18 rentals that all have old style round tanks if the tank is lasting less than 10 years you got a used tank or bad luck. We do a yearly tank flush ( 10-20 gallons into a bucket/ drain) and check the pop off and once in awhile change the rod and that's it! We also have extremely hard water.

[@laloajuria4678]

imagine if it was just a heat pump with 200-300% efficiency.

[@paulgaras2606]

Love heat pumps but air to water is real challenge for heating. Not heat pumps fault. Most existing radiators are designed for 180 degree water and that’s really hard to achieve with the heat pumps on the market today… or really like ever.

[@waltercurtis6930]

Hope they provided a bigger electric panel given it’s a good chance in 30 years they will not be able to replace In kind due restrictions on gas usage.

[@jonh1808]

Average combi lifespan is 15 years if a condensing appliance. The heat exchangers deteriorate over time from the acidity of the condensate. Not a prayer of getting 30 years out of it. You can keep them going if the manufacturer still supplies parts but as with anything else, you get to the point where you may as well stop throwing spares around and just get a new one. They do go through parts like they’re off out of fashion. Get on good terms with whoever will be repairing it. That’s not a criticism of this manufacturer, in the UK the majority of homes have combi boilers and they are all as bad in that respect, I’ve been repairing them for 25 years. Like cars, it’s where the manufacturers make their money.

[@802Leith]

Try a heat pump in -30 f not so good here in New England

[@balzacq]

@@waltercurtis6930 I have one very much like this. In 30 years I'll probably be dead, so not too worried about it.

[@beachboardfan9544]

Whats the control board cost? Thats always what fails and it always costs just enough to make it not worth replacing just the board so they sell you a whole unit instead...

[@allon33]

Works, in theory. How about you switch it on, and see how well it performs in real life. And how many air changes per day with that small duct?

[@anthonykaiser974]

In New England, so not exactly TX or the lower Midwest.

[@deanrows]

That intro tho

[@MustPassTruck]

Some of the combi models are hard to find. They keep going out of stock.

[@SkilledLabor]

It’s great, UNTIL there’s a problem and you don’t have heat or hot water!

[@kevinwilliams1421]

If your only getting combi boilers now…you will be getting condensing boilers soon enough

[@urchin11]

zero explanation of how a combo boiler works or can be used

[@3joewj]

The previous boiler will out last the combi boiler by 20 years minimum...by the way radiators are a much better heat than hot air. Bad move! My opinion...I'd never do it.

[@SkaterStimm]

I think there was a different voice in the beginning of the video. Since I am the first to call it out, can I win something ;-)

[@nunyabidness3075]

Aren’t they worried about gas supply in New England with New York playing politics on pipelines?

[@mrstinky2421]

No current worries other than cooking appliances

[@nunyabidness3075]

@@mrstinky2421 You mean being able to buy the appliances? I’m seriously wondering about getting enough gas to meet demand. I really don’t get the nonsense with pipelines through New York. Seems like a 10th amendment violation to me.

[@stormagorist6129]

Water heater. Hot water needs no heating, unless you are making steam then it is a steamer...It's embarrassing, or should be, to be a tradesman or even tangentially involved with the trades and make this sort of gaffe.. (look it up)

[@drumdude10]

🙄

[@aaronorr5586]

@@drumdude10 Ikr, autism levels of pedantry.

[@anthonykaiser974]

English is not a monolithic language. Lots of languages have features that may seem redundant. In some, the double negative is actually correct, for example.

[@stormagorist6129]

@@anthonykaiser974 Good luck disproving identity and the law of non-contradiction, but nice red herring..