On delivery your hot tub will most probably be packed vertically. It is important that the hot tub is not kept in this transport position for a long time. If it was delivered in the normal horizontal way, there is a pallet or crate attached to the bottom for the transportation. This pallet or crate must be unscrewed and removed before setting the hot tub to its final position.

There are certain things that are good to take into consideration before using the hot tub. Wood is a living material and it reacts to varying weather conditions. One of the most influential factors concerning wood is humidity. If the air humidity percentage is high the wood will swell and when the air humidity percentage lowers the wood will shrink. Thermally treated wood swells and shrinks about a quarter less than untreated wood. Therefore it is excellent for hot tubs.

The hot tub must be placed on an even foundation that will bear the full weight of the hot tub, water and bathers. Gravel can be used to make the ground more even (as shown in the picture) or if a more solid base is preferred it can be made of concrete. We recommend placing a few treated planks under the barrel to ensure adequate airflow beneath it. Make sure that the hot tub is not placed directly onto the ground or any other area where grass/weeds can grow underneath or around it limiting the airflow. This circulation of air flow is important.

Take into account the location of the water exit pipe so that emptying can be carried out without causing damage. The 5m of flexi outlet hose and stop-cock can be easily be attached to the 50mm exit pipe.

Fire Safety

If the hot tub is located near buildings, for example on the side of a terrace, the distance of the chimney from any combustible materials must be adequate.

Remember to check the distance both laterally and vertically so that there isn’t any risk of fire. Safe minimum distance laterally is three (3) meters. If the chimney is closer to any combustible material you must use special insulated chimney, which has to be purchased separately. When positioned close to the roof or when taken through it, the top end of the insulated chimney must be at least one (1) meter above the surface of the roof.

Notice also the fire safety in front of the furnace. There shouldn’t be any flammable materials near the furnace. There should be an area that is made of incombustible material such as concrete, sand or metal.

Grates

For the CUBE heater, two cast iron grates and one L-formed iron plate will be delivered. Those are to be positioned on the tracks in the heater. The order of the grates is shown on the right side. Formed iron plate is to be installed bended edge upwards. It will deflect the air and also prevent the firewood to drop out from the heater.

Never start the fire when the hot tub is empty or the water level is insufficient! If there is not enough water in the hot tub and the fire is started this will melt the stove! The hot tub must always be filled so that the water level is at least 5 cm above the upper pipes of the stove (picture right). Only then it is safe to start the fire. Do not have more than the recommended number of bathers in the hot tub as this can lead to displacing sufficient water to bring the level below the upper pipe. This could then cause the inside of the CUBE heater to melt if it is still hot.

Assembling the chimney

Your hot tub will be delivered pre-assembled. The chimney is delivered in the separate box and consists of 4 pieces shown on the picture right. First, fix the hat on the sparking net with three wing nuts (C, assembled in the picture). Attach the hat to the first part’s (B) straight end, so that it lays on the holders. Next, attach the second part (B) so that the contracted end is downwards. Then place the assembled chimney inside the protective sleeve (A) so that the chimney’s contracted end stays visible. Finally, fit the contracted end of the assembled chimney inside the stove and pull the protective sleeve as far down as it goes.

Tightness of the hot tub

When you use the hot tub for the first time, it is worth noticing that some wooden planks may leak. Water will come through where there have been knots and possibly through the joints of the grooves. This is a normal phenomenon, which will stop after the first few uses.

When using the hot tub for the first time you have to use more water to fill it up than later on. Heating the water will make the hot tub swell and tighten faster. The metal bands of the hot tubs won’t need to be tightened if the hot tub is put into use immediately. The hot tub will become fully watertight if you use it often.

Cover

If you purchased your hot tub with an ABS plastic cover it will come with a fastening set that secures it to the hot tub itself (see the picture below). With the fastening set the cover will stay on even in windy weather. Covering studs are attached to the hot tub above the upper metal band (see the picture below) with screws. Make sure that the studs are attached in line with the hooks on the cover. The rubber bands are then used to hold down the cover. Plywood covers will stay down in windy conditions under their own weight.

First-time use

Before using the hot tub for the first time it is recommended that you rinse the water circulating system of the stove. Hose water through the upper pipe of the stove so that possible chips of metal or other dirt left from processing will come out. This dirt can be wiped from the bottom of the hot tub. When you are filling up the hot tub, check the pipes that attach the stove to the barrel in case of leakages. Tighten the clamps of the pipes if necessary.

Even a Thermowood hot tub dries out and may possibly get leaky if it is out of use for a long time – this will go however as soon as you start to use it again. Before using the hot tub for the first time, it is recommended to check the tightness of the sideboards, especially near the bottom. You should tighten the metal bands if they seem loose. This will help to speed up the swelling process of the hot tub. There are two tighteners on the outer side of the hot tub (see picture below) for which you can fit 19 mm spanner or socket. With these tighteners you can adjust the bands suitably tight.

When you are filling a dry hot tub, we recommend wetting the whole hot tub so that the water would soak into the wood faster.

If you are using your own pump to fill up the hot tub, remove the pumping hose after the hot tub is filled. Many pumps do not have a non-return-valve and the water can flow back out of the hot tub after the pump has been turned off. Remember to check that the plug is in its place before filling up the hot tub. The plug is near the stove on the bottom of the hot tub.

Do not overheat the water. We recommend a bathing temperature of between 36-38°C.

While heating the water, it is advisable to keep up a fair sized fire in the stove so that the wood would burn properly and the maximum output would be achieved.

Empty ash from the stove after every use. If the fire grates inside remain covered in ash it will shorten the lifetime of the grates considerably. Ash pan should be taken out of the stove during heating. The ash pan is meant only for emptying out the ashes. The ash pan will bend and be ruined and it will also block the airflow if it is left in the stove while heating.

Use only dry wood for heating the stove. We do not recommend the use of common alder as firewood in our stoves, because it will cause more soot and also stickier soot compared to other firewood.

We recommend the use of firelighters to start the fire.

Safety and care

We recommend covering the hot tub while not in use. This will prevent leaves etc entering the hot tub. However, the hot tub shouldn’t be covered too tightly because the wood needs to be able to “breath” from inside the hot tub as well.

Hot tubs made out of Thermowood have a beautiful brown color. If you want to maintain the same shade of brown, the outside of the barrel should be oiled about once a year with tree oil that contains UV protection, or with tar balsam. Do not use any liquids for the inside walls of the hot tub.

The lifetime of your hot tub will be significantly extended if it is cared for and cleaned regularly. The inside of the hot tub is best washed with a scrubbing brush and sanitiser. If the hot tub is for public use, we recommend the use of chlorine. This chlorine should be mixed first with a small amount of water before being added to the bathing water. See chlorine manufacturer’s recommendations for advice on concentrations.

Do not allow children to play unattended in or around the hot tub.

Be careful with the steps which may become slippery when wet or in cold weather when the spilled water may freeze and become slippery as well.

Having contagious skin disease is a good reason to avoid communal bathing. Bathers with heart conditions are advised to keep water temperature well below 37°C.

THE WOODEN HOT TUB COMPANY wishes you an enjoyable hot tub experience!