Welcome to this first Möbius Update post of 2022! I hope you have 2022 off to a great start already as we work to do the same here aboard the Good Ship Möbius. I am slowly warming up to getting back to weekly blog posts here so thanks very much for your patience in waiting for this first one of the new year. I’ve been warming up particularly well now that I have the in floor heating all working which I think may well be Captain Christine’s favorite feature so far.
With the weather getting colder since our return at the beginning of December from our 2 months back in Canada and the USA, I’ve been mostly working on getting all the Domestic Hot Water or DHW systems fully operational and all the various bugs worked out. I’ve received a number of questions about how our DHW system works and what components we have installed and a lot of interest in the in-floor heating system we’ve installed and that’s what Ill do my best to cover here in this week’s update.
Domestic Hot Water System
Our DHW system is pretty straight forward so let me cover that first.
Hot Water circulation Loop that runs around the circumference of the boat
Ours is the “Combi” model which means that it has two separate heating loops inside. The primary loop heats up the water in the IsoTherm Calorifier which holds all the DHW for the boat and the other loop heats up the fluid going to the four air handlers which can heat the air in each cabin if needed.
This view of the back of the Kabola shows the primary boiler loop Supply/Return connections at #1 & #2 and then the secondary loop flows in/out of #5 & 6. The Primary loop has a built in circulation pump that constantly circulates the antifreeze/water fluid and a thermostat turns the burner on/off to keep the fluid at whatever temperature you set.
The secondary “Combi” loop has an external circulation pump that is part of the Webasto AirCon/Heating system.
I’ve removed the front of the burner to show you how the internal heat exchangers work. The large black tank you see on the Left contains all the antifreeze/water fluid and the diesel burner is inside the Grey tube on the Right.
The larger diameter tubes/holes on the top are the secondary loop and the larger number on the bottom are the primary heating loop.
The Kabola is super simple to operate, just turn it on, set the thermostat to be whatever degrees you want the internal fluid inside the boiler to maintain and then pretty much forget it. When the fluid temp goes down the burner automatically fires up, heats the water a bit past the set temp and then shuts off. Could not be simpler or more efficient.
Now let’s follow where the heated fluid as it leaves the Kabola and flows over to the heat exchanger loop inside the Calorifier.
This cutaway view shows how our IsoTherm Calorifier is similarly multi purposed with three different sources of heat to keep our DHW nice and hot. There are two loops of SS pipes on the bottom here, one which has the fluid from the Kabola flowing in/out of it and the other loop a similar antifreeze/water fluid flowing through from the Gardner engine’s “cooling” system. The top most loop is a 240V electric heating element that we can use if needed.
All SS construction and the outside never even gets warm so the heavy insulation has been working very well and the Kabola does not need to fire up very often to keep the water nice and hot all the time.
Turning the Calorifier above around and looking at the outside this sketch shows the three pairs of In/Out connections; one for the hot fluid from the Kabola, one for the hot fluid from the Gardner (when it is running) and then the Cold Fresh Water In and DHW Out.
The end of the Calorifier in the illustration above is under my hand and if you look closely (click to enlarge any photo) you can see a Yellow ring labelled “Engine Water” on the far Right and a White ring on the Left labelled “Kabola White” On the top Right the Red Label marks where the Hot Water comes out through the black wrapped insulated pipes which are split into one line going to the DHW loop and the other with the bottom Left Mixing Valve going to the In Floor Heating loops.
Closer view of the adjustable Mixing Valve which controls the temperature of the water going out to the In Floor Heating system which wants warm not Hot water, usually about 55C/131F whereas the DHW runs about 65C/150F.
To make sure there is always hot water ready to come out of each sink and shower, the DHW flows around the whole boat in a continuous loop of insulated pipe. In this schematic the DHW loop is on the Right hand side and the In/Out to the In Floor Heating is on the Left.
To keep the DHW flowing through the hot water loop feeding each tap and shower, this magnetically coupled impeller pump is very small, about the size of your fist and is highly efficiency with very low power consumption and absolutely silent.
We now have very hot water readily available at every tap and shower onboard and we are both eXtremely pleased with how well the whole DHW system has been working.
In-Floor Heating or IFH
Winters here in southern Turkey are rather mild compared to many locations with lows down to 8C/46F a few nights and day time highs as much as 20C/68F but winter is also when we get rainy days and so can get chilly and so the real star of our DHW system the past while has been having nice warm floors throughout the boat to keep us toasty warm.
It has taken me some time to get it all adjusted and working properly but it is now running flawlessly and silently so let me walk you through how this system works.
As with the DHW system above, the In Floor Heating or IFH is a very simple system with the following main components:
An Azel I-Link controller with three thermostats for each IFH zone on the boat, one in each cabin and one in the SuperSalon.
A pair of SS manifolds, top Red one where the Warm water (about 50C/122F coming in at the top and then the Returning slightly cooler water exiting out the bottom Blue manifold.
Each of the I-Link thermostats controls one of these Taco 3 speed 1/25HP circulation pumps which circulates the fresh DHW water from the Calorifier through the PEX tubing that runs in loops underneath all our floors as needed to keep our tootsies nice and warm.
We worked out these serpentine patterns of PEX tubing in each of the three Zones to provide an even distribution of heat wherever there were bare floors and not under the built in furniture. This is in the Master Cabin; Head/shower lower Left, bed center Right.
This is how the PEX tubing was laid down before the 10mm marine plywood floors were installed. Serpentine grooves were cut into the foam with a router.
Foil tape was set into the groove in the foam and then the 15mm PEX tubing was press fit into the groove.
Here is how it looked in the forward end of the SuperSalon.
Let’s take a minute to walk through a brief explanation of how the In Floor Heating system works.
For our IFH system I decided to use what is called the “Open Direct” style as it is incredibly simple and efficient. OPEN in this case refers to the fact that the IFH system is “open” to the same DHW that we use onboard for sinks and showers. A “closed” system would be like the loops of antifreeze/water that the Kabola uses to heat up the water in the Calorifier.
DIRECT refers to the fact that the fresh warm water flowing through the PEX tubing is heating the floors directly, not through a heat exchanger like those in the Calorifier.
This simple schematic adds the details of how the IFH portion of our DHW system works. Warm water coming out of the Calorifier via the mixing valve is pumped on demand through the PEX tubing in the floors by the Taco circulation pumps.
Part of the simple brilliance of an Open Direct system is that the DHW always takes precedence so anytime you turn on a hot water tap or the shower, hot water is diverted to them until shut of when the warm water returns to circulate through the floors as needed. Huh? How does THAT work you ask? The following two illustrations should help make sense of this very simple but initially a bit confusing system works.
This is In Floor Heating Mode that happens whenever the thermostat for this IFH Zone turns the circulation pump ON and warm DHW is pumped through the under floor PEX tubing in that zone and then returned back to the Calorifier (Water Heater). Keep in mind that even though the whole DHW system is pressurized to about 4 Bar/60 PSI in this mode the ONLY way water flows is IF the circulation pump is running.
Even though it is available, Cold water cannot enter the system when the pump comes on unless someone is taking hot water out of the system by taking a shower, doing dishes, etc..
When a Hot water tap is opened then the pressure drops and the system reverts to this DHW Mode and Hot water flows out of the Calorifier (Water Heater) to the HW tap and Cold water flows into the system to replace it.
The cold water goes through heating tubes within the floor on its way to the water heater. This flow pattern provides limited free cooling and other benefits. Stagnation is prevented and
priority is given to the domestic hot water use over the space heating use. A small amount of free cooling is realized in the summer.
Note that NO additional equipment, parts or power is needed to make these two modes work automatically.
Brilliantly simple don’t you think??!!
I found these beautiful SS manifolds on Amazon for a great price and they made the whole plumbing of the system very straightforward to install and control. Red handled ball valve top Left is where the warm water from the Calorifier flows INTO the system and is made available to each of the three Red Flow Control Meters/Valves and into the PEX fittings on the bottom.
Cooler water from each continuous PEX loop flows into the bottom three fittings, each with the White capped control valve and then OUT the Blue ball valve and back to the Calorifier.
Each continuous loop of PEX in a zone has one of these Red Flow Meters that you adjust to get the correct flow rate, which is about 1-1.5 L/min for our zones.
Each ball valve has a temp gauge so you can check the differential of the water temp coming IN and how much it drops going OUT. Ideal is about 50C/122F coming in and 40C/104 going OUT and you adjust this via the Mixing Valve on the Calorifier.
Here is what the whole IFH manifold looks like when assembled and installed with the three Taco circulation pumps.
These Taco pumps are pretty much bullet proof and are miserly power consumers as they are very small 1/25HP AC motors.
The Taco pumps are absolutely silent and can be run at one of three speed settings to get you the flow you want. They are also dead quiet and you can only tell they are running by watching the flow meters.
This Azel I-Link controller is the brains of the IFH system and takes its orders from one of the three thermostats conveniently located in each Zone.
Each thermostat is very easy to adjust and provides a full set of information of room temp, floor temp, when the “heating mode” or pumps are on, etc..
Here is what one looks like in operation today. Room temp is 22.3C/72F, Set Point is 24C, floor temp is 49C.
Each Zone has one of these little temperature sensors installed which connects to the thermostat of that Zone so it and the controller knows when to turn the circulation pump Off/On.
The main control box of the I-Link system is carefully tucked away into a small alcove in the Ship’s Office where it is well protected but easily viewed by opening the cupboard door. Red lights on the far Right indicate when one of the 3 zones is working (pump on).
And that is it! Just like the Kabola boiler, this is a “set it and forget it” system and has been working flawlessly and very easy to adjust as we learned what temps we liked in each zone.
You have to experience it to understand just how fabulous Toasty Tootsies are when the weather turns colder outside!
And that’s a wrap for this week, the first blog and Möbius Update of 2022 is done and dusted!
Hope you enjoyed it and please be sure to tell me if you did or didn’t and add any other questions in the “Join the Discussion” box below.
I’ll do my best to be back again next weekend with another Möbius Update for you and thanks again for your patience in waiting for this one to go live.